Merge branch 'js/blame-lib'

The internal logic used in "git blame" has been libified to make it
easier to use by cgit.

* js/blame-lib: (29 commits)
  blame: move entry prepend to libgit
  blame: move scoreboard setup to libgit
  blame: move scoreboard-related methods to libgit
  blame: move fake-commit-related methods to libgit
  blame: move origin-related methods to libgit
  blame: move core structures to header
  blame: create entry prepend function
  blame: create scoreboard setup function
  blame: create scoreboard init function
  blame: rework methods that determine 'final' commit
  blame: wrap blame_sort and compare_blame_final
  blame: move progress updates to a scoreboard callback
  blame: make sanity_check use a callback in scoreboard
  blame: move no_whole_file_rename flag to scoreboard
  blame: move xdl_opts flags to scoreboard
  blame: move show_root flag to scoreboard
  blame: move reverse flag to scoreboard
  blame: move contents_from to scoreboard
  blame: move copy/move thresholds to scoreboard
  blame: move stat counters to scoreboard
  ...

8 files changed, 2134 insertions, 2050 deletions

diff --git a/Makefile b/Makefile
index 22e4ef3ac5..7c621f7f76 100644
--- a/Makefile
+++ b/Makefile
@@ -720,6 +720,7 @@ LIB_OBJS += argv-array.o
 LIB_OBJS += attr.o
 LIB_OBJS += base85.o
 LIB_OBJS += bisect.o
+LIB_OBJS += blame.o
 LIB_OBJS += blob.o
 LIB_OBJS += branch.o
 LIB_OBJS += bulk-checkin.o
diff --git a/blame.c b/blame.c
new file mode 100644
index 0000000000..843c845cba
--- /dev/null
+++ b/blame.c
@@ -0,0 +1,1863 @@
+#include "cache.h"
+#include "refs.h"
+#include "cache-tree.h"
+#include "mergesort.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "tag.h"
+#include "blame.h"
+
+void blame_origin_decref(struct blame_origin *o)
+{
+	if (o && --o->refcnt <= 0) {
+		struct blame_origin *p, *l = NULL;
+		if (o->previous)
+			blame_origin_decref(o->previous);
+		free(o->file.ptr);
+		/* Should be present exactly once in commit chain */
+		for (p = o->commit->util; p; l = p, p = p->next) {
+			if (p == o) {
+				if (l)
+					l->next = p->next;
+				else
+					o->commit->util = p->next;
+				free(o);
+				return;
+			}
+		}
+		die("internal error in blame_origin_decref");
+	}
+}
+
+/*
+ * Given a commit and a path in it, create a new origin structure.
+ * The callers that add blame to the scoreboard should use
+ * get_origin() to obtain shared, refcounted copy instead of calling
+ * this function directly.
+ */
+static struct blame_origin *make_origin(struct commit *commit, const char *path)
+{
+	struct blame_origin *o;
+	FLEX_ALLOC_STR(o, path, path);
+	o->commit = commit;
+	o->refcnt = 1;
+	o->next = commit->util;
+	commit->util = o;
+	return o;
+}
+
+/*
+ * Locate an existing origin or create a new one.
+ * This moves the origin to front position in the commit util list.
+ */
+static struct blame_origin *get_origin(struct commit *commit, const char *path)
+{
+	struct blame_origin *o, *l;
+
+	for (o = commit->util, l = NULL; o; l = o, o = o->next) {
+		if (!strcmp(o->path, path)) {
+			/* bump to front */
+			if (l) {
+				l->next = o->next;
+				o->next = commit->util;
+				commit->util = o;
+			}
+			return blame_origin_incref(o);
+		}
+	}
+	return make_origin(commit, path);
+}
+
+
+
+static void verify_working_tree_path(struct commit *work_tree, const char *path)
+{
+	struct commit_list *parents;
+	int pos;
+
+	for (parents = work_tree->parents; parents; parents = parents->next) {
+		const struct object_id *commit_oid = &parents->item->object.oid;
+		struct object_id blob_oid;
+		unsigned mode;
+
+		if (!get_tree_entry(commit_oid->hash, path, blob_oid.hash, &mode) &&
+		    sha1_object_info(blob_oid.hash, NULL) == OBJ_BLOB)
+			return;
+	}
+
+	pos = cache_name_pos(path, strlen(path));
+	if (pos >= 0)
+		; /* path is in the index */
+	else if (-1 - pos < active_nr &&
+		 !strcmp(active_cache[-1 - pos]->name, path))
+		; /* path is in the index, unmerged */
+	else
+		die("no such path '%s' in HEAD", path);
+}
+
+static struct commit_list **append_parent(struct commit_list **tail, const struct object_id *oid)
+{
+	struct commit *parent;
+
+	parent = lookup_commit_reference(oid);
+	if (!parent)
+		die("no such commit %s", oid_to_hex(oid));
+	return &commit_list_insert(parent, tail)->next;
+}
+
+static void append_merge_parents(struct commit_list **tail)
+{
+	int merge_head;
+	struct strbuf line = STRBUF_INIT;
+
+	merge_head = open(git_path_merge_head(), O_RDONLY);
+	if (merge_head < 0) {
+		if (errno == ENOENT)
+			return;
+		die("cannot open '%s' for reading", git_path_merge_head());
+	}
+
+	while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) {
+		struct object_id oid;
+		if (line.len < GIT_SHA1_HEXSZ || get_oid_hex(line.buf, &oid))
+			die("unknown line in '%s': %s", git_path_merge_head(), line.buf);
+		tail = append_parent(tail, &oid);
+	}
+	close(merge_head);
+	strbuf_release(&line);
+}
+
+/*
+ * This isn't as simple as passing sb->buf and sb->len, because we
+ * want to transfer ownership of the buffer to the commit (so we
+ * must use detach).
+ */
+static void set_commit_buffer_from_strbuf(struct commit *c, struct strbuf *sb)
+{
+	size_t len;
+	void *buf = strbuf_detach(sb, &len);
+	set_commit_buffer(c, buf, len);
+}
+
+/*
+ * Prepare a dummy commit that represents the work tree (or staged) item.
+ * Note that annotating work tree item never works in the reverse.
+ */
+static struct commit *fake_working_tree_commit(struct diff_options *opt,
+					       const char *path,
+					       const char *contents_from)
+{
+	struct commit *commit;
+	struct blame_origin *origin;
+	struct commit_list **parent_tail, *parent;
+	struct object_id head_oid;
+	struct strbuf buf = STRBUF_INIT;
+	const char *ident;
+	time_t now;
+	int size, len;
+	struct cache_entry *ce;
+	unsigned mode;
+	struct strbuf msg = STRBUF_INIT;
+
+	read_cache();
+	time(&now);
+	commit = alloc_commit_node();
+	commit->object.parsed = 1;
+	commit->date = now;
+	parent_tail = &commit->parents;
+
+	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_oid.hash, NULL))
+		die("no such ref: HEAD");
+
+	parent_tail = append_parent(parent_tail, &head_oid);
+	append_merge_parents(parent_tail);
+	verify_working_tree_path(commit, path);
+
+	origin = make_origin(commit, path);
+
+	ident = fmt_ident("Not Committed Yet", "not.committed.yet", NULL, 0);
+	strbuf_addstr(&msg, "tree 0000000000000000000000000000000000000000\n");
+	for (parent = commit->parents; parent; parent = parent->next)
+		strbuf_addf(&msg, "parent %s\n",
+			    oid_to_hex(&parent->item->object.oid));
+	strbuf_addf(&msg,
+		    "author %s\n"
+		    "committer %s\n\n"
+		    "Version of %s from %s\n",
+		    ident, ident, path,
+		    (!contents_from ? path :
+		     (!strcmp(contents_from, "-") ? "standard input" : contents_from)));
+	set_commit_buffer_from_strbuf(commit, &msg);
+
+	if (!contents_from || strcmp("-", contents_from)) {
+		struct stat st;
+		const char *read_from;
+		char *buf_ptr;
+		unsigned long buf_len;
+
+		if (contents_from) {
+			if (stat(contents_from, &st) < 0)
+				die_errno("Cannot stat '%s'", contents_from);
+			read_from = contents_from;
+		}
+		else {
+			if (lstat(path, &st) < 0)
+				die_errno("Cannot lstat '%s'", path);
+			read_from = path;
+		}
+		mode = canon_mode(st.st_mode);
+
+		switch (st.st_mode & S_IFMT) {
+		case S_IFREG:
+			if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV) &&
+			    textconv_object(read_from, mode, &null_oid, 0, &buf_ptr, &buf_len))
+				strbuf_attach(&buf, buf_ptr, buf_len, buf_len + 1);
+			else if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size)
+				die_errno("cannot open or read '%s'", read_from);
+			break;
+		case S_IFLNK:
+			if (strbuf_readlink(&buf, read_from, st.st_size) < 0)
+				die_errno("cannot readlink '%s'", read_from);
+			break;
+		default:
+			die("unsupported file type %s", read_from);
+		}
+	}
+	else {
+		/* Reading from stdin */
+		mode = 0;
+		if (strbuf_read(&buf, 0, 0) < 0)
+			die_errno("failed to read from stdin");
+	}
+	convert_to_git(path, buf.buf, buf.len, &buf, 0);
+	origin->file.ptr = buf.buf;
+	origin->file.size = buf.len;
+	pretend_sha1_file(buf.buf, buf.len, OBJ_BLOB, origin->blob_oid.hash);
+
+	/*
+	 * Read the current index, replace the path entry with
+	 * origin->blob_sha1 without mucking with its mode or type
+	 * bits; we are not going to write this index out -- we just
+	 * want to run "diff-index --cached".
+	 */
+	discard_cache();
+	read_cache();
+
+	len = strlen(path);
+	if (!mode) {
+		int pos = cache_name_pos(path, len);
+		if (0 <= pos)
+			mode = active_cache[pos]->ce_mode;
+		else
+			/* Let's not bother reading from HEAD tree */
+			mode = S_IFREG | 0644;
+	}
+	size = cache_entry_size(len);
+	ce = xcalloc(1, size);
+	oidcpy(&ce->oid, &origin->blob_oid);
+	memcpy(ce->name, path, len);
+	ce->ce_flags = create_ce_flags(0);
+	ce->ce_namelen = len;
+	ce->ce_mode = create_ce_mode(mode);
+	add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
+
+	cache_tree_invalidate_path(&the_index, path);
+
+	return commit;
+}
+
+
+
+static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b,
+		      xdl_emit_hunk_consume_func_t hunk_func, void *cb_data, int xdl_opts)
+{
+	xpparam_t xpp = {0};
+	xdemitconf_t xecfg = {0};
+	xdemitcb_t ecb = {NULL};
+
+	xpp.flags = xdl_opts;
+	xecfg.hunk_func = hunk_func;
+	ecb.priv = cb_data;
+	return xdi_diff(file_a, file_b, &xpp, &xecfg, &ecb);
+}
+
+/*
+ * Given an origin, prepare mmfile_t structure to be used by the
+ * diff machinery
+ */
+static void fill_origin_blob(struct diff_options *opt,
+			     struct blame_origin *o, mmfile_t *file, int *num_read_blob)
+{
+	if (!o->file.ptr) {
+		enum object_type type;
+		unsigned long file_size;
+
+		(*num_read_blob)++;
+		if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV) &&
+		    textconv_object(o->path, o->mode, &o->blob_oid, 1, &file->ptr, &file_size))
+			;
+		else
+			file->ptr = read_sha1_file(o->blob_oid.hash, &type,
+						   &file_size);
+		file->size = file_size;
+
+		if (!file->ptr)
+			die("Cannot read blob %s for path %s",
+			    oid_to_hex(&o->blob_oid),
+			    o->path);
+		o->file = *file;
+	}
+	else
+		*file = o->file;
+}
+
+static void drop_origin_blob(struct blame_origin *o)
+{
+	if (o->file.ptr) {
+		free(o->file.ptr);
+		o->file.ptr = NULL;
+	}
+}
+
+/*
+ * Any merge of blames happens on lists of blames that arrived via
+ * different parents in a single suspect.  In this case, we want to
+ * sort according to the suspect line numbers as opposed to the final
+ * image line numbers.  The function body is somewhat longish because
+ * it avoids unnecessary writes.
+ */
+
+static struct blame_entry *blame_merge(struct blame_entry *list1,
+				       struct blame_entry *list2)
+{
+	struct blame_entry *p1 = list1, *p2 = list2,
+		**tail = &list1;
+
+	if (!p1)
+		return p2;
+	if (!p2)
+		return p1;
+
+	if (p1->s_lno <= p2->s_lno) {
+		do {
+			tail = &p1->next;
+			if ((p1 = *tail) == NULL) {
+				*tail = p2;
+				return list1;
+			}
+		} while (p1->s_lno <= p2->s_lno);
+	}
+	for (;;) {
+		*tail = p2;
+		do {
+			tail = &p2->next;
+			if ((p2 = *tail) == NULL)  {
+				*tail = p1;
+				return list1;
+			}
+		} while (p1->s_lno > p2->s_lno);
+		*tail = p1;
+		do {
+			tail = &p1->next;
+			if ((p1 = *tail) == NULL) {
+				*tail = p2;
+				return list1;
+			}
+		} while (p1->s_lno <= p2->s_lno);
+	}
+}
+
+static void *get_next_blame(const void *p)
+{
+	return ((struct blame_entry *)p)->next;
+}
+
+static void set_next_blame(void *p1, void *p2)
+{
+	((struct blame_entry *)p1)->next = p2;
+}
+
+/*
+ * Final image line numbers are all different, so we don't need a
+ * three-way comparison here.
+ */
+
+static int compare_blame_final(const void *p1, const void *p2)
+{
+	return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno
+		? 1 : -1;
+}
+
+static int compare_blame_suspect(const void *p1, const void *p2)
+{
+	const struct blame_entry *s1 = p1, *s2 = p2;
+	/*
+	 * to allow for collating suspects, we sort according to the
+	 * respective pointer value as the primary sorting criterion.
+	 * The actual relation is pretty unimportant as long as it
+	 * establishes a total order.  Comparing as integers gives us
+	 * that.
+	 */
+	if (s1->suspect != s2->suspect)
+		return (intptr_t)s1->suspect > (intptr_t)s2->suspect ? 1 : -1;
+	if (s1->s_lno == s2->s_lno)
+		return 0;
+	return s1->s_lno > s2->s_lno ? 1 : -1;
+}
+
+void blame_sort_final(struct blame_scoreboard *sb)
+{
+	sb->ent = llist_mergesort(sb->ent, get_next_blame, set_next_blame,
+				  compare_blame_final);
+}
+
+static int compare_commits_by_reverse_commit_date(const void *a,
+						  const void *b,
+						  void *c)
+{
+	return -compare_commits_by_commit_date(a, b, c);
+}
+
+/*
+ * For debugging -- origin is refcounted, and this asserts that
+ * we do not underflow.
+ */
+static void sanity_check_refcnt(struct blame_scoreboard *sb)
+{
+	int baa = 0;
+	struct blame_entry *ent;
+
+	for (ent = sb->ent; ent; ent = ent->next) {
+		/* Nobody should have zero or negative refcnt */
+		if (ent->suspect->refcnt <= 0) {
+			fprintf(stderr, "%s in %s has negative refcnt %d\n",
+				ent->suspect->path,
+				oid_to_hex(&ent->suspect->commit->object.oid),
+				ent->suspect->refcnt);
+			baa = 1;
+		}
+	}
+	if (baa)
+		sb->on_sanity_fail(sb, baa);
+}
+
+/*
+ * If two blame entries that are next to each other came from
+ * contiguous lines in the same origin (i.e. <commit, path> pair),
+ * merge them together.
+ */
+void blame_coalesce(struct blame_scoreboard *sb)
+{
+	struct blame_entry *ent, *next;
+
+	for (ent = sb->ent; ent && (next = ent->next); ent = next) {
+		if (ent->suspect == next->suspect &&
+		    ent->s_lno + ent->num_lines == next->s_lno) {
+			ent->num_lines += next->num_lines;
+			ent->next = next->next;
+			blame_origin_decref(next->suspect);
+			free(next);
+			ent->score = 0;
+			next = ent; /* again */
+		}
+	}
+
+	if (sb->debug) /* sanity */
+		sanity_check_refcnt(sb);
+}
+
+/*
+ * Merge the given sorted list of blames into a preexisting origin.
+ * If there were no previous blames to that commit, it is entered into
+ * the commit priority queue of the score board.
+ */
+
+static void queue_blames(struct blame_scoreboard *sb, struct blame_origin *porigin,
+			 struct blame_entry *sorted)
+{
+	if (porigin->suspects)
+		porigin->suspects = blame_merge(porigin->suspects, sorted);
+	else {
+		struct blame_origin *o;
+		for (o = porigin->commit->util; o; o = o->next) {
+			if (o->suspects) {
+				porigin->suspects = sorted;
+				return;
+			}
+		}
+		porigin->suspects = sorted;
+		prio_queue_put(&sb->commits, porigin->commit);
+	}
+}
+
+/*
+ * Fill the blob_sha1 field of an origin if it hasn't, so that later
+ * call to fill_origin_blob() can use it to locate the data.  blob_sha1
+ * for an origin is also used to pass the blame for the entire file to
+ * the parent to detect the case where a child's blob is identical to
+ * that of its parent's.
+ *
+ * This also fills origin->mode for corresponding tree path.
+ */
+static int fill_blob_sha1_and_mode(struct blame_origin *origin)
+{
+	if (!is_null_oid(&origin->blob_oid))
+		return 0;
+	if (get_tree_entry(origin->commit->object.oid.hash,
+			   origin->path,
+			   origin->blob_oid.hash, &origin->mode))
+		goto error_out;
+	if (sha1_object_info(origin->blob_oid.hash, NULL) != OBJ_BLOB)
+		goto error_out;
+	return 0;
+ error_out:
+	oidclr(&origin->blob_oid);
+	origin->mode = S_IFINVALID;
+	return -1;
+}
+
+/*
+ * We have an origin -- check if the same path exists in the
+ * parent and return an origin structure to represent it.
+ */
+static struct blame_origin *find_origin(struct commit *parent,
+				  struct blame_origin *origin)
+{
+	struct blame_origin *porigin;
+	struct diff_options diff_opts;
+	const char *paths[2];
+
+	/* First check any existing origins */
+	for (porigin = parent->util; porigin; porigin = porigin->next)
+		if (!strcmp(porigin->path, origin->path)) {
+			/*
+			 * The same path between origin and its parent
+			 * without renaming -- the most common case.
+			 */
+			return blame_origin_incref (porigin);
+		}
+
+	/* See if the origin->path is different between parent
+	 * and origin first.  Most of the time they are the
+	 * same and diff-tree is fairly efficient about this.
+	 */
+	diff_setup(&diff_opts);
+	DIFF_OPT_SET(&diff_opts, RECURSIVE);
+	diff_opts.detect_rename = 0;
+	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+	paths[0] = origin->path;
+	paths[1] = NULL;
+
+	parse_pathspec(&diff_opts.pathspec,
+		       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
+		       PATHSPEC_LITERAL_PATH, "", paths);
+	diff_setup_done(&diff_opts);
+
+	if (is_null_oid(&origin->commit->object.oid))
+		do_diff_cache(&parent->tree->object.oid, &diff_opts);
+	else
+		diff_tree_sha1(parent->tree->object.oid.hash,
+			       origin->commit->tree->object.oid.hash,
+			       "", &diff_opts);
+	diffcore_std(&diff_opts);
+
+	if (!diff_queued_diff.nr) {
+		/* The path is the same as parent */
+		porigin = get_origin(parent, origin->path);
+		oidcpy(&porigin->blob_oid, &origin->blob_oid);
+		porigin->mode = origin->mode;
+	} else {
+		/*
+		 * Since origin->path is a pathspec, if the parent
+		 * commit had it as a directory, we will see a whole
+		 * bunch of deletion of files in the directory that we
+		 * do not care about.
+		 */
+		int i;
+		struct diff_filepair *p = NULL;
+		for (i = 0; i < diff_queued_diff.nr; i++) {
+			const char *name;
+			p = diff_queued_diff.queue[i];
+			name = p->one->path ? p->one->path : p->two->path;
+			if (!strcmp(name, origin->path))
+				break;
+		}
+		if (!p)
+			die("internal error in blame::find_origin");
+		switch (p->status) {
+		default:
+			die("internal error in blame::find_origin (%c)",
+			    p->status);
+		case 'M':
+			porigin = get_origin(parent, origin->path);
+			oidcpy(&porigin->blob_oid, &p->one->oid);
+			porigin->mode = p->one->mode;
+			break;
+		case 'A':
+		case 'T':
+			/* Did not exist in parent, or type changed */
+			break;
+		}
+	}
+	diff_flush(&diff_opts);
+	clear_pathspec(&diff_opts.pathspec);
+	return porigin;
+}
+
+/*
+ * We have an origin -- find the path that corresponds to it in its
+ * parent and return an origin structure to represent it.
+ */
+static struct blame_origin *find_rename(struct commit *parent,
+				  struct blame_origin *origin)
+{
+	struct blame_origin *porigin = NULL;
+	struct diff_options diff_opts;
+	int i;
+
+	diff_setup(&diff_opts);
+	DIFF_OPT_SET(&diff_opts, RECURSIVE);
+	diff_opts.detect_rename = DIFF_DETECT_RENAME;
+	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+	diff_opts.single_follow = origin->path;
+	diff_setup_done(&diff_opts);
+
+	if (is_null_oid(&origin->commit->object.oid))
+		do_diff_cache(&parent->tree->object.oid, &diff_opts);
+	else
+		diff_tree_sha1(parent->tree->object.oid.hash,
+			       origin->commit->tree->object.oid.hash,
+			       "", &diff_opts);
+	diffcore_std(&diff_opts);
+
+	for (i = 0; i < diff_queued_diff.nr; i++) {
+		struct diff_filepair *p = diff_queued_diff.queue[i];
+		if ((p->status == 'R' || p->status == 'C') &&
+		    !strcmp(p->two->path, origin->path)) {
+			porigin = get_origin(parent, p->one->path);
+			oidcpy(&porigin->blob_oid, &p->one->oid);
+			porigin->mode = p->one->mode;
+			break;
+		}
+	}
+	diff_flush(&diff_opts);
+	clear_pathspec(&diff_opts.pathspec);
+	return porigin;
+}
+
+/*
+ * Append a new blame entry to a given output queue.
+ */
+static void add_blame_entry(struct blame_entry ***queue,
+			    const struct blame_entry *src)
+{
+	struct blame_entry *e = xmalloc(sizeof(*e));
+	memcpy(e, src, sizeof(*e));
+	blame_origin_incref(e->suspect);
+
+	e->next = **queue;
+	**queue = e;
+	*queue = &e->next;
+}
+
+/*
+ * src typically is on-stack; we want to copy the information in it to
+ * a malloced blame_entry that gets added to the given queue.  The
+ * origin of dst loses a refcnt.
+ */
+static void dup_entry(struct blame_entry ***queue,
+		      struct blame_entry *dst, struct blame_entry *src)
+{
+	blame_origin_incref(src->suspect);
+	blame_origin_decref(dst->suspect);
+	memcpy(dst, src, sizeof(*src));
+	dst->next = **queue;
+	**queue = dst;
+	*queue = &dst->next;
+}
+
+const char *blame_nth_line(struct blame_scoreboard *sb, long lno)
+{
+	return sb->final_buf + sb->lineno[lno];
+}
+
+/*
+ * It is known that lines between tlno to same came from parent, and e
+ * has an overlap with that range.  it also is known that parent's
+ * line plno corresponds to e's line tlno.
+ *
+ *                <---- e ----->
+ *                   <------>
+ *                   <------------>
+ *             <------------>
+ *             <------------------>
+ *
+ * Split e into potentially three parts; before this chunk, the chunk
+ * to be blamed for the parent, and after that portion.
+ */
+static void split_overlap(struct blame_entry *split,
+			  struct blame_entry *e,
+			  int tlno, int plno, int same,
+			  struct blame_origin *parent)
+{
+	int chunk_end_lno;
+	memset(split, 0, sizeof(struct blame_entry [3]));
+
+	if (e->s_lno < tlno) {
+		/* there is a pre-chunk part not blamed on parent */
+		split[0].suspect = blame_origin_incref(e->suspect);
+		split[0].lno = e->lno;
+		split[0].s_lno = e->s_lno;
+		split[0].num_lines = tlno - e->s_lno;
+		split[1].lno = e->lno + tlno - e->s_lno;
+		split[1].s_lno = plno;
+	}
+	else {
+		split[1].lno = e->lno;
+		split[1].s_lno = plno + (e->s_lno - tlno);
+	}
+
+	if (same < e->s_lno + e->num_lines) {
+		/* there is a post-chunk part not blamed on parent */
+		split[2].suspect = blame_origin_incref(e->suspect);
+		split[2].lno = e->lno + (same - e->s_lno);
+		split[2].s_lno = e->s_lno + (same - e->s_lno);
+		split[2].num_lines = e->s_lno + e->num_lines - same;
+		chunk_end_lno = split[2].lno;
+	}
+	else
+		chunk_end_lno = e->lno + e->num_lines;
+	split[1].num_lines = chunk_end_lno - split[1].lno;
+
+	/*
+	 * if it turns out there is nothing to blame the parent for,
+	 * forget about the splitting.  !split[1].suspect signals this.
+	 */
+	if (split[1].num_lines < 1)
+		return;
+	split[1].suspect = blame_origin_incref(parent);
+}
+
+/*
+ * split_overlap() divided an existing blame e into up to three parts
+ * in split.  Any assigned blame is moved to queue to
+ * reflect the split.
+ */
+static void split_blame(struct blame_entry ***blamed,
+			struct blame_entry ***unblamed,
+			struct blame_entry *split,
+			struct blame_entry *e)
+{
+	if (split[0].suspect && split[2].suspect) {
+		/* The first part (reuse storage for the existing entry e) */
+		dup_entry(unblamed, e, &split[0]);
+
+		/* The last part -- me */
+		add_blame_entry(unblamed, &split[2]);
+
+		/* ... and the middle part -- parent */
+		add_blame_entry(blamed, &split[1]);
+	}
+	else if (!split[0].suspect && !split[2].suspect)
+		/*
+		 * The parent covers the entire area; reuse storage for
+		 * e and replace it with the parent.
+		 */
+		dup_entry(blamed, e, &split[1]);
+	else if (split[0].suspect) {
+		/* me and then parent */
+		dup_entry(unblamed, e, &split[0]);
+		add_blame_entry(blamed, &split[1]);
+	}
+	else {
+		/* parent and then me */
+		dup_entry(blamed, e, &split[1]);
+		add_blame_entry(unblamed, &split[2]);
+	}
+}
+
+/*
+ * After splitting the blame, the origins used by the
+ * on-stack blame_entry should lose one refcnt each.
+ */
+static void decref_split(struct blame_entry *split)
+{
+	int i;
+
+	for (i = 0; i < 3; i++)
+		blame_origin_decref(split[i].suspect);
+}
+
+/*
+ * reverse_blame reverses the list given in head, appending tail.
+ * That allows us to build lists in reverse order, then reverse them
+ * afterwards.  This can be faster than building the list in proper
+ * order right away.  The reason is that building in proper order
+ * requires writing a link in the _previous_ element, while building
+ * in reverse order just requires placing the list head into the
+ * _current_ element.
+ */
+
+static struct blame_entry *reverse_blame(struct blame_entry *head,
+					 struct blame_entry *tail)
+{
+	while (head) {
+		struct blame_entry *next = head->next;
+		head->next = tail;
+		tail = head;
+		head = next;
+	}
+	return tail;
+}
+
+/*
+ * Process one hunk from the patch between the current suspect for
+ * blame_entry e and its parent.  This first blames any unfinished
+ * entries before the chunk (which is where target and parent start
+ * differing) on the parent, and then splits blame entries at the
+ * start and at the end of the difference region.  Since use of -M and
+ * -C options may lead to overlapping/duplicate source line number
+ * ranges, all we can rely on from sorting/merging is the order of the
+ * first suspect line number.
+ */
+static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
+			int tlno, int offset, int same,
+			struct blame_origin *parent)
+{
+	struct blame_entry *e = **srcq;
+	struct blame_entry *samep = NULL, *diffp = NULL;
+
+	while (e && e->s_lno < tlno) {
+		struct blame_entry *next = e->next;
+		/*
+		 * current record starts before differing portion.  If
+		 * it reaches into it, we need to split it up and
+		 * examine the second part separately.
+		 */
+		if (e->s_lno + e->num_lines > tlno) {
+			/* Move second half to a new record */
+			int len = tlno - e->s_lno;
+			struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
+			n->suspect = e->suspect;
+			n->lno = e->lno + len;
+			n->s_lno = e->s_lno + len;
+			n->num_lines = e->num_lines - len;
+			e->num_lines = len;
+			e->score = 0;
+			/* Push new record to diffp */
+			n->next = diffp;
+			diffp = n;
+		} else
+			blame_origin_decref(e->suspect);
+		/* Pass blame for everything before the differing
+		 * chunk to the parent */
+		e->suspect = blame_origin_incref(parent);
+		e->s_lno += offset;
+		e->next = samep;
+		samep = e;
+		e = next;
+	}
+	/*
+	 * As we don't know how much of a common stretch after this
+	 * diff will occur, the currently blamed parts are all that we
+	 * can assign to the parent for now.
+	 */
+
+	if (samep) {
+		**dstq = reverse_blame(samep, **dstq);
+		*dstq = &samep->next;
+	}
+	/*
+	 * Prepend the split off portions: everything after e starts
+	 * after the blameable portion.
+	 */
+	e = reverse_blame(diffp, e);
+
+	/*
+	 * Now retain records on the target while parts are different
+	 * from the parent.
+	 */
+	samep = NULL;
+	diffp = NULL;
+	while (e && e->s_lno < same) {
+		struct blame_entry *next = e->next;
+
+		/*
+		 * If current record extends into sameness, need to split.
+		 */
+		if (e->s_lno + e->num_lines > same) {
+			/*
+			 * Move second half to a new record to be
+			 * processed by later chunks
+			 */
+			int len = same - e->s_lno;
+			struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
+			n->suspect = blame_origin_incref(e->suspect);
+			n->lno = e->lno + len;
+			n->s_lno = e->s_lno + len;
+			n->num_lines = e->num_lines - len;
+			e->num_lines = len;
+			e->score = 0;
+			/* Push new record to samep */
+			n->next = samep;
+			samep = n;
+		}
+		e->next = diffp;
+		diffp = e;
+		e = next;
+	}
+	**srcq = reverse_blame(diffp, reverse_blame(samep, e));
+	/* Move across elements that are in the unblamable portion */
+	if (diffp)
+		*srcq = &diffp->next;
+}
+
+struct blame_chunk_cb_data {
+	struct blame_origin *parent;
+	long offset;
+	struct blame_entry **dstq;
+	struct blame_entry **srcq;
+};
+
+/* diff chunks are from parent to target */
+static int blame_chunk_cb(long start_a, long count_a,
+			  long start_b, long count_b, void *data)
+{
+	struct blame_chunk_cb_data *d = data;
+	if (start_a - start_b != d->offset)
+		die("internal error in blame::blame_chunk_cb");
+	blame_chunk(&d->dstq, &d->srcq, start_b, start_a - start_b,
+		    start_b + count_b, d->parent);
+	d->offset = start_a + count_a - (start_b + count_b);
+	return 0;
+}
+
+/*
+ * We are looking at the origin 'target' and aiming to pass blame
+ * for the lines it is suspected to its parent.  Run diff to find
+ * which lines came from parent and pass blame for them.
+ */
+static void pass_blame_to_parent(struct blame_scoreboard *sb,
+				 struct blame_origin *target,
+				 struct blame_origin *parent)
+{
+	mmfile_t file_p, file_o;
+	struct blame_chunk_cb_data d;
+	struct blame_entry *newdest = NULL;
+
+	if (!target->suspects)
+		return; /* nothing remains for this target */
+
+	d.parent = parent;
+	d.offset = 0;
+	d.dstq = &newdest; d.srcq = &target->suspects;
+
+	fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob);
+	fill_origin_blob(&sb->revs->diffopt, target, &file_o, &sb->num_read_blob);
+	sb->num_get_patch++;
+
+	if (diff_hunks(&file_p, &file_o, blame_chunk_cb, &d, sb->xdl_opts))
+		die("unable to generate diff (%s -> %s)",
+		    oid_to_hex(&parent->commit->object.oid),
+		    oid_to_hex(&target->commit->object.oid));
+	/* The rest are the same as the parent */
+	blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, parent);
+	*d.dstq = NULL;
+	queue_blames(sb, parent, newdest);
+
+	return;
+}
+
+/*
+ * The lines in blame_entry after splitting blames many times can become
+ * very small and trivial, and at some point it becomes pointless to
+ * blame the parents.  E.g. "\t\t}\n\t}\n\n" appears everywhere in any
+ * ordinary C program, and it is not worth to say it was copied from
+ * totally unrelated file in the parent.
+ *
+ * Compute how trivial the lines in the blame_entry are.
+ */
+unsigned blame_entry_score(struct blame_scoreboard *sb, struct blame_entry *e)
+{
+	unsigned score;
+	const char *cp, *ep;
+
+	if (e->score)
+		return e->score;
+
+	score = 1;
+	cp = blame_nth_line(sb, e->lno);
+	ep = blame_nth_line(sb, e->lno + e->num_lines);
+	while (cp < ep) {
+		unsigned ch = *((unsigned char *)cp);
+		if (isalnum(ch))
+			score++;
+		cp++;
+	}
+	e->score = score;
+	return score;
+}
+
+/*
+ * best_so_far[] and this[] are both a split of an existing blame_entry
+ * that passes blame to the parent.  Maintain best_so_far the best split
+ * so far, by comparing this and best_so_far and copying this into
+ * bst_so_far as needed.
+ */
+static void copy_split_if_better(struct blame_scoreboard *sb,
+				 struct blame_entry *best_so_far,
+				 struct blame_entry *this)
+{
+	int i;
+
+	if (!this[1].suspect)
+		return;
+	if (best_so_far[1].suspect) {
+		if (blame_entry_score(sb, &this[1]) < blame_entry_score(sb, &best_so_far[1]))
+			return;
+	}
+
+	for (i = 0; i < 3; i++)
+		blame_origin_incref(this[i].suspect);
+	decref_split(best_so_far);
+	memcpy(best_so_far, this, sizeof(struct blame_entry [3]));
+}
+
+/*
+ * We are looking at a part of the final image represented by
+ * ent (tlno and same are offset by ent->s_lno).
+ * tlno is where we are looking at in the final image.
+ * up to (but not including) same match preimage.
+ * plno is where we are looking at in the preimage.
+ *
+ * <-------------- final image ---------------------->
+ *       <------ent------>
+ *         ^tlno ^same
+ *    <---------preimage----->
+ *         ^plno
+ *
+ * All line numbers are 0-based.
+ */
+static void handle_split(struct blame_scoreboard *sb,
+			 struct blame_entry *ent,
+			 int tlno, int plno, int same,
+			 struct blame_origin *parent,
+			 struct blame_entry *split)
+{
+	if (ent->num_lines <= tlno)
+		return;
+	if (tlno < same) {
+		struct blame_entry this[3];
+		tlno += ent->s_lno;
+		same += ent->s_lno;
+		split_overlap(this, ent, tlno, plno, same, parent);
+		copy_split_if_better(sb, split, this);
+		decref_split(this);
+	}
+}
+
+struct handle_split_cb_data {
+	struct blame_scoreboard *sb;
+	struct blame_entry *ent;
+	struct blame_origin *parent;
+	struct blame_entry *split;
+	long plno;
+	long tlno;
+};
+
+static int handle_split_cb(long start_a, long count_a,
+			   long start_b, long count_b, void *data)
+{
+	struct handle_split_cb_data *d = data;
+	handle_split(d->sb, d->ent, d->tlno, d->plno, start_b, d->parent,
+		     d->split);
+	d->plno = start_a + count_a;
+	d->tlno = start_b + count_b;
+	return 0;
+}
+
+/*
+ * Find the lines from parent that are the same as ent so that
+ * we can pass blames to it.  file_p has the blob contents for
+ * the parent.
+ */
+static void find_copy_in_blob(struct blame_scoreboard *sb,
+			      struct blame_entry *ent,
+			      struct blame_origin *parent,
+			      struct blame_entry *split,
+			      mmfile_t *file_p)
+{
+	const char *cp;
+	mmfile_t file_o;
+	struct handle_split_cb_data d;
+
+	memset(&d, 0, sizeof(d));
+	d.sb = sb; d.ent = ent; d.parent = parent; d.split = split;
+	/*
+	 * Prepare mmfile that contains only the lines in ent.
+	 */
+	cp = blame_nth_line(sb, ent->lno);
+	file_o.ptr = (char *) cp;
+	file_o.size = blame_nth_line(sb, ent->lno + ent->num_lines) - cp;
+
+	/*
+	 * file_o is a part of final image we are annotating.
+	 * file_p partially may match that image.
+	 */
+	memset(split, 0, sizeof(struct blame_entry [3]));
+	if (diff_hunks(file_p, &file_o, handle_split_cb, &d, sb->xdl_opts))
+		die("unable to generate diff (%s)",
+		    oid_to_hex(&parent->commit->object.oid));
+	/* remainder, if any, all match the preimage */
+	handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
+}
+
+/* Move all blame entries from list *source that have a score smaller
+ * than score_min to the front of list *small.
+ * Returns a pointer to the link pointing to the old head of the small list.
+ */
+
+static struct blame_entry **filter_small(struct blame_scoreboard *sb,
+					 struct blame_entry **small,
+					 struct blame_entry **source,
+					 unsigned score_min)
+{
+	struct blame_entry *p = *source;
+	struct blame_entry *oldsmall = *small;
+	while (p) {
+		if (blame_entry_score(sb, p) <= score_min) {
+			*small = p;
+			small = &p->next;
+			p = *small;
+		} else {
+			*source = p;
+			source = &p->next;
+			p = *source;
+		}
+	}
+	*small = oldsmall;
+	*source = NULL;
+	return small;
+}
+
+/*
+ * See if lines currently target is suspected for can be attributed to
+ * parent.
+ */
+static void find_move_in_parent(struct blame_scoreboard *sb,
+				struct blame_entry ***blamed,
+				struct blame_entry **toosmall,
+				struct blame_origin *target,
+				struct blame_origin *parent)
+{
+	struct blame_entry *e, split[3];
+	struct blame_entry *unblamed = target->suspects;
+	struct blame_entry *leftover = NULL;
+	mmfile_t file_p;
+
+	if (!unblamed)
+		return; /* nothing remains for this target */
+
+	fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob);
+	if (!file_p.ptr)
+		return;
+
+	/* At each iteration, unblamed has a NULL-terminated list of
+	 * entries that have not yet been tested for blame.  leftover
+	 * contains the reversed list of entries that have been tested
+	 * without being assignable to the parent.
+	 */
+	do {
+		struct blame_entry **unblamedtail = &unblamed;
+		struct blame_entry *next;
+		for (e = unblamed; e; e = next) {
+			next = e->next;
+			find_copy_in_blob(sb, e, parent, split, &file_p);
+			if (split[1].suspect &&
+			    sb->move_score < blame_entry_score(sb, &split[1])) {
+				split_blame(blamed, &unblamedtail, split, e);
+			} else {
+				e->next = leftover;
+				leftover = e;
+			}
+			decref_split(split);
+		}
+		*unblamedtail = NULL;
+		toosmall = filter_small(sb, toosmall, &unblamed, sb->move_score);
+	} while (unblamed);
+	target->suspects = reverse_blame(leftover, NULL);
+}
+
+struct blame_list {
+	struct blame_entry *ent;
+	struct blame_entry split[3];
+};
+
+/*
+ * Count the number of entries the target is suspected for,
+ * and prepare a list of entry and the best split.
+ */
+static struct blame_list *setup_blame_list(struct blame_entry *unblamed,
+					   int *num_ents_p)
+{
+	struct blame_entry *e;
+	int num_ents, i;
+	struct blame_list *blame_list = NULL;
+
+	for (e = unblamed, num_ents = 0; e; e = e->next)
+		num_ents++;
+	if (num_ents) {
+		blame_list = xcalloc(num_ents, sizeof(struct blame_list));
+		for (e = unblamed, i = 0; e; e = e->next)
+			blame_list[i++].ent = e;
+	}
+	*num_ents_p = num_ents;
+	return blame_list;
+}
+
+/*
+ * For lines target is suspected for, see if we can find code movement
+ * across file boundary from the parent commit.  porigin is the path
+ * in the parent we already tried.
+ */
+static void find_copy_in_parent(struct blame_scoreboard *sb,
+				struct blame_entry ***blamed,
+				struct blame_entry **toosmall,
+				struct blame_origin *target,
+				struct commit *parent,
+				struct blame_origin *porigin,
+				int opt)
+{
+	struct diff_options diff_opts;
+	int i, j;
+	struct blame_list *blame_list;
+	int num_ents;
+	struct blame_entry *unblamed = target->suspects;
+	struct blame_entry *leftover = NULL;
+
+	if (!unblamed)
+		return; /* nothing remains for this target */
+
+	diff_setup(&diff_opts);
+	DIFF_OPT_SET(&diff_opts, RECURSIVE);
+	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+
+	diff_setup_done(&diff_opts);
+
+	/* Try "find copies harder" on new path if requested;
+	 * we do not want to use diffcore_rename() actually to
+	 * match things up; find_copies_harder is set only to
+	 * force diff_tree_sha1() to feed all filepairs to diff_queue,
+	 * and this code needs to be after diff_setup_done(), which
+	 * usually makes find-copies-harder imply copy detection.
+	 */
+	if ((opt & PICKAXE_BLAME_COPY_HARDEST)
+	    || ((opt & PICKAXE_BLAME_COPY_HARDER)
+		&& (!porigin || strcmp(target->path, porigin->path))))
+		DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
+
+	if (is_null_oid(&target->commit->object.oid))
+		do_diff_cache(&parent->tree->object.oid, &diff_opts);
+	else
+		diff_tree_sha1(parent->tree->object.oid.hash,
+			       target->commit->tree->object.oid.hash,
+			       "", &diff_opts);
+
+	if (!DIFF_OPT_TST(&diff_opts, FIND_COPIES_HARDER))
+		diffcore_std(&diff_opts);
+
+	do {
+		struct blame_entry **unblamedtail = &unblamed;
+		blame_list = setup_blame_list(unblamed, &num_ents);
+
+		for (i = 0; i < diff_queued_diff.nr; i++) {
+			struct diff_filepair *p = diff_queued_diff.queue[i];
+			struct blame_origin *norigin;
+			mmfile_t file_p;
+			struct blame_entry this[3];
+
+			if (!DIFF_FILE_VALID(p->one))
+				continue; /* does not exist in parent */
+			if (S_ISGITLINK(p->one->mode))
+				continue; /* ignore git links */
+			if (porigin && !strcmp(p->one->path, porigin->path))
+				/* find_move already dealt with this path */
+				continue;
+
+			norigin = get_origin(parent, p->one->path);
+			oidcpy(&norigin->blob_oid, &p->one->oid);
+			norigin->mode = p->one->mode;
+			fill_origin_blob(&sb->revs->diffopt, norigin, &file_p, &sb->num_read_blob);
+			if (!file_p.ptr)
+				continue;
+
+			for (j = 0; j < num_ents; j++) {
+				find_copy_in_blob(sb, blame_list[j].ent,
+						  norigin, this, &file_p);
+				copy_split_if_better(sb, blame_list[j].split,
+						     this);
+				decref_split(this);
+			}
+			blame_origin_decref(norigin);
+		}
+
+		for (j = 0; j < num_ents; j++) {
+			struct blame_entry *split = blame_list[j].split;
+			if (split[1].suspect &&
+			    sb->copy_score < blame_entry_score(sb, &split[1])) {
+				split_blame(blamed, &unblamedtail, split,
+					    blame_list[j].ent);
+			} else {
+				blame_list[j].ent->next = leftover;
+				leftover = blame_list[j].ent;
+			}
+			decref_split(split);
+		}
+		free(blame_list);
+		*unblamedtail = NULL;
+		toosmall = filter_small(sb, toosmall, &unblamed, sb->copy_score);
+	} while (unblamed);
+	target->suspects = reverse_blame(leftover, NULL);
+	diff_flush(&diff_opts);
+	clear_pathspec(&diff_opts.pathspec);
+}
+
+/*
+ * The blobs of origin and porigin exactly match, so everything
+ * origin is suspected for can be blamed on the parent.
+ */
+static void pass_whole_blame(struct blame_scoreboard *sb,
+			     struct blame_origin *origin, struct blame_origin *porigin)
+{
+	struct blame_entry *e, *suspects;
+
+	if (!porigin->file.ptr && origin->file.ptr) {
+		/* Steal its file */
+		porigin->file = origin->file;
+		origin->file.ptr = NULL;
+	}
+	suspects = origin->suspects;
+	origin->suspects = NULL;
+	for (e = suspects; e; e = e->next) {
+		blame_origin_incref(porigin);
+		blame_origin_decref(e->suspect);
+		e->suspect = porigin;
+	}
+	queue_blames(sb, porigin, suspects);
+}
+
+/*
+ * We pass blame from the current commit to its parents.  We keep saying
+ * "parent" (and "porigin"), but what we mean is to find scapegoat to
+ * exonerate ourselves.
+ */
+static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit,
+					int reverse)
+{
+	if (!reverse) {
+		if (revs->first_parent_only &&
+		    commit->parents &&
+		    commit->parents->next) {
+			free_commit_list(commit->parents->next);
+			commit->parents->next = NULL;
+		}
+		return commit->parents;
+	}
+	return lookup_decoration(&revs->children, &commit->object);
+}
+
+static int num_scapegoats(struct rev_info *revs, struct commit *commit, int reverse)
+{
+	struct commit_list *l = first_scapegoat(revs, commit, reverse);
+	return commit_list_count(l);
+}
+
+/* Distribute collected unsorted blames to the respected sorted lists
+ * in the various origins.
+ */
+static void distribute_blame(struct blame_scoreboard *sb, struct blame_entry *blamed)
+{
+	blamed = llist_mergesort(blamed, get_next_blame, set_next_blame,
+				 compare_blame_suspect);
+	while (blamed)
+	{
+		struct blame_origin *porigin = blamed->suspect;
+		struct blame_entry *suspects = NULL;
+		do {
+			struct blame_entry *next = blamed->next;
+			blamed->next = suspects;
+			suspects = blamed;
+			blamed = next;
+		} while (blamed && blamed->suspect == porigin);
+		suspects = reverse_blame(suspects, NULL);
+		queue_blames(sb, porigin, suspects);
+	}
+}
+
+#define MAXSG 16
+
+static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin, int opt)
+{
+	struct rev_info *revs = sb->revs;
+	int i, pass, num_sg;
+	struct commit *commit = origin->commit;
+	struct commit_list *sg;
+	struct blame_origin *sg_buf[MAXSG];
+	struct blame_origin *porigin, **sg_origin = sg_buf;
+	struct blame_entry *toosmall = NULL;
+	struct blame_entry *blames, **blametail = &blames;
+
+	num_sg = num_scapegoats(revs, commit, sb->reverse);
+	if (!num_sg)
+		goto finish;
+	else if (num_sg < ARRAY_SIZE(sg_buf))
+		memset(sg_buf, 0, sizeof(sg_buf));
+	else
+		sg_origin = xcalloc(num_sg, sizeof(*sg_origin));
+
+	/*
+	 * The first pass looks for unrenamed path to optimize for
+	 * common cases, then we look for renames in the second pass.
+	 */
+	for (pass = 0; pass < 2 - sb->no_whole_file_rename; pass++) {
+		struct blame_origin *(*find)(struct commit *, struct blame_origin *);
+		find = pass ? find_rename : find_origin;
+
+		for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
+		     i < num_sg && sg;
+		     sg = sg->next, i++) {
+			struct commit *p = sg->item;
+			int j, same;
+
+			if (sg_origin[i])
+				continue;
+			if (parse_commit(p))
+				continue;
+			porigin = find(p, origin);
+			if (!porigin)
+				continue;
+			if (!oidcmp(&porigin->blob_oid, &origin->blob_oid)) {
+				pass_whole_blame(sb, origin, porigin);
+				blame_origin_decref(porigin);
+				goto finish;
+			}
+			for (j = same = 0; j < i; j++)
+				if (sg_origin[j] &&
+				    !oidcmp(&sg_origin[j]->blob_oid, &porigin->blob_oid)) {
+					same = 1;
+					break;
+				}
+			if (!same)
+				sg_origin[i] = porigin;
+			else
+				blame_origin_decref(porigin);
+		}
+	}
+
+	sb->num_commits++;
+	for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
+	     i < num_sg && sg;
+	     sg = sg->next, i++) {
+		struct blame_origin *porigin = sg_origin[i];
+		if (!porigin)
+			continue;
+		if (!origin->previous) {
+			blame_origin_incref(porigin);
+			origin->previous = porigin;
+		}
+		pass_blame_to_parent(sb, origin, porigin);
+		if (!origin->suspects)
+			goto finish;
+	}
+
+	/*
+	 * Optionally find moves in parents' files.
+	 */
+	if (opt & PICKAXE_BLAME_MOVE) {
+		filter_small(sb, &toosmall, &origin->suspects, sb->move_score);
+		if (origin->suspects) {
+			for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
+			     i < num_sg && sg;
+			     sg = sg->next, i++) {
+				struct blame_origin *porigin = sg_origin[i];
+				if (!porigin)
+					continue;
+				find_move_in_parent(sb, &blametail, &toosmall, origin, porigin);
+				if (!origin->suspects)
+					break;
+			}
+		}
+	}
+
+	/*
+	 * Optionally find copies from parents' files.
+	 */
+	if (opt & PICKAXE_BLAME_COPY) {
+		if (sb->copy_score > sb->move_score)
+			filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
+		else if (sb->copy_score < sb->move_score) {
+			origin->suspects = blame_merge(origin->suspects, toosmall);
+			toosmall = NULL;
+			filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
+		}
+		if (!origin->suspects)
+			goto finish;
+
+		for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
+		     i < num_sg && sg;
+		     sg = sg->next, i++) {
+			struct blame_origin *porigin = sg_origin[i];
+			find_copy_in_parent(sb, &blametail, &toosmall,
+					    origin, sg->item, porigin, opt);
+			if (!origin->suspects)
+				goto finish;
+		}
+	}
+
+finish:
+	*blametail = NULL;
+	distribute_blame(sb, blames);
+	/*
+	 * prepend toosmall to origin->suspects
+	 *
+	 * There is no point in sorting: this ends up on a big
+	 * unsorted list in the caller anyway.
+	 */
+	if (toosmall) {
+		struct blame_entry **tail = &toosmall;
+		while (*tail)
+			tail = &(*tail)->next;
+		*tail = origin->suspects;
+		origin->suspects = toosmall;
+	}
+	for (i = 0; i < num_sg; i++) {
+		if (sg_origin[i]) {
+			drop_origin_blob(sg_origin[i]);
+			blame_origin_decref(sg_origin[i]);
+		}
+	}
+	drop_origin_blob(origin);
+	if (sg_buf != sg_origin)
+		free(sg_origin);
+}
+
+/*
+ * The main loop -- while we have blobs with lines whose true origin
+ * is still unknown, pick one blob, and allow its lines to pass blames
+ * to its parents. */
+void assign_blame(struct blame_scoreboard *sb, int opt)
+{
+	struct rev_info *revs = sb->revs;
+	struct commit *commit = prio_queue_get(&sb->commits);
+
+	while (commit) {
+		struct blame_entry *ent;
+		struct blame_origin *suspect = commit->util;
+
+		/* find one suspect to break down */
+		while (suspect && !suspect->suspects)
+			suspect = suspect->next;
+
+		if (!suspect) {
+			commit = prio_queue_get(&sb->commits);
+			continue;
+		}
+
+		assert(commit == suspect->commit);
+
+		/*
+		 * We will use this suspect later in the loop,
+		 * so hold onto it in the meantime.
+		 */
+		blame_origin_incref(suspect);
+		parse_commit(commit);
+		if (sb->reverse ||
+		    (!(commit->object.flags & UNINTERESTING) &&
+		     !(revs->max_age != -1 && commit->date < revs->max_age)))
+			pass_blame(sb, suspect, opt);
+		else {
+			commit->object.flags |= UNINTERESTING;
+			if (commit->object.parsed)
+				mark_parents_uninteresting(commit);
+		}
+		/* treat root commit as boundary */
+		if (!commit->parents && !sb->show_root)
+			commit->object.flags |= UNINTERESTING;
+
+		/* Take responsibility for the remaining entries */
+		ent = suspect->suspects;
+		if (ent) {
+			suspect->guilty = 1;
+			for (;;) {
+				struct blame_entry *next = ent->next;
+				if (sb->found_guilty_entry)
+					sb->found_guilty_entry(ent, sb->found_guilty_entry_data);
+				if (next) {
+					ent = next;
+					continue;
+				}
+				ent->next = sb->ent;
+				sb->ent = suspect->suspects;
+				suspect->suspects = NULL;
+				break;
+			}
+		}
+		blame_origin_decref(suspect);
+
+		if (sb->debug) /* sanity */
+			sanity_check_refcnt(sb);
+	}
+}
+
+static const char *get_next_line(const char *start, const char *end)
+{
+	const char *nl = memchr(start, '\n', end - start);
+	return nl ? nl + 1 : end;
+}
+
+/*
+ * To allow quick access to the contents of nth line in the
+ * final image, prepare an index in the scoreboard.
+ */
+static int prepare_lines(struct blame_scoreboard *sb)
+{
+	const char *buf = sb->final_buf;
+	unsigned long len = sb->final_buf_size;
+	const char *end = buf + len;
+	const char *p;
+	int *lineno;
+	int num = 0;
+
+	for (p = buf; p < end; p = get_next_line(p, end))
+		num++;
+
+	ALLOC_ARRAY(sb->lineno, num + 1);
+	lineno = sb->lineno;
+
+	for (p = buf; p < end; p = get_next_line(p, end))
+		*lineno++ = p - buf;
+
+	*lineno = len;
+
+	sb->num_lines = num;
+	return sb->num_lines;
+}
+
+static struct commit *find_single_final(struct rev_info *revs,
+					const char **name_p)
+{
+	int i;
+	struct commit *found = NULL;
+	const char *name = NULL;
+
+	for (i = 0; i < revs->pending.nr; i++) {
+		struct object *obj = revs->pending.objects[i].item;
+		if (obj->flags & UNINTERESTING)
+			continue;
+		obj = deref_tag(obj, NULL, 0);
+		if (obj->type != OBJ_COMMIT)
+			die("Non commit %s?", revs->pending.objects[i].name);
+		if (found)
+			die("More than one commit to dig from %s and %s?",
+			    revs->pending.objects[i].name, name);
+		found = (struct commit *)obj;
+		name = revs->pending.objects[i].name;
+	}
+	if (name_p)
+		*name_p = name;
+	return found;
+}
+
+static struct commit *dwim_reverse_initial(struct rev_info *revs,
+					   const char **name_p)
+{
+	/*
+	 * DWIM "git blame --reverse ONE -- PATH" as
+	 * "git blame --reverse ONE..HEAD -- PATH" but only do so
+	 * when it makes sense.
+	 */
+	struct object *obj;
+	struct commit *head_commit;
+	struct object_id head_oid;
+
+	if (revs->pending.nr != 1)
+		return NULL;
+
+	/* Is that sole rev a committish? */
+	obj = revs->pending.objects[0].item;
+	obj = deref_tag(obj, NULL, 0);
+	if (obj->type != OBJ_COMMIT)
+		return NULL;
+
+	/* Do we have HEAD? */
+	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_oid.hash, NULL))
+		return NULL;
+	head_commit = lookup_commit_reference_gently(&head_oid, 1);
+	if (!head_commit)
+		return NULL;
+
+	/* Turn "ONE" into "ONE..HEAD" then */
+	obj->flags |= UNINTERESTING;
+	add_pending_object(revs, &head_commit->object, "HEAD");
+
+	if (name_p)
+		*name_p = revs->pending.objects[0].name;
+	return (struct commit *)obj;
+}
+
+static struct commit *find_single_initial(struct rev_info *revs,
+					  const char **name_p)
+{
+	int i;
+	struct commit *found = NULL;
+	const char *name = NULL;
+
+	/*
+	 * There must be one and only one negative commit, and it must be
+	 * the boundary.
+	 */
+	for (i = 0; i < revs->pending.nr; i++) {
+		struct object *obj = revs->pending.objects[i].item;
+		if (!(obj->flags & UNINTERESTING))
+			continue;
+		obj = deref_tag(obj, NULL, 0);
+		if (obj->type != OBJ_COMMIT)
+			die("Non commit %s?", revs->pending.objects[i].name);
+		if (found)
+			die("More than one commit to dig up from, %s and %s?",
+			    revs->pending.objects[i].name, name);
+		found = (struct commit *) obj;
+		name = revs->pending.objects[i].name;
+	}
+
+	if (!name)
+		found = dwim_reverse_initial(revs, &name);
+	if (!name)
+		die("No commit to dig up from?");
+
+	if (name_p)
+		*name_p = name;
+	return found;
+}
+
+void init_scoreboard(struct blame_scoreboard *sb)
+{
+	memset(sb, 0, sizeof(struct blame_scoreboard));
+	sb->move_score = BLAME_DEFAULT_MOVE_SCORE;
+	sb->copy_score = BLAME_DEFAULT_COPY_SCORE;
+}
+
+void setup_scoreboard(struct blame_scoreboard *sb, const char *path, struct blame_origin **orig)
+{
+	const char *final_commit_name = NULL;
+	struct blame_origin *o;
+	struct commit *final_commit = NULL;
+	enum object_type type;
+
+	if (sb->reverse && sb->contents_from)
+		die(_("--contents and --reverse do not blend well."));
+
+	if (!sb->reverse) {
+		sb->final = find_single_final(sb->revs, &final_commit_name);
+		sb->commits.compare = compare_commits_by_commit_date;
+	} else {
+		sb->final = find_single_initial(sb->revs, &final_commit_name);
+		sb->commits.compare = compare_commits_by_reverse_commit_date;
+	}
+
+	if (sb->final && sb->contents_from)
+		die(_("cannot use --contents with final commit object name"));
+
+	if (sb->reverse && sb->revs->first_parent_only)
+		sb->revs->children.name = NULL;
+
+	if (!sb->final) {
+		/*
+		 * "--not A B -- path" without anything positive;
+		 * do not default to HEAD, but use the working tree
+		 * or "--contents".
+		 */
+		setup_work_tree();
+		sb->final = fake_working_tree_commit(&sb->revs->diffopt,
+						     path, sb->contents_from);
+		add_pending_object(sb->revs, &(sb->final->object), ":");
+	}
+
+	if (sb->reverse && sb->revs->first_parent_only) {
+		final_commit = find_single_final(sb->revs, NULL);
+		if (!final_commit)
+			die(_("--reverse and --first-parent together require specified latest commit"));
+	}
+
+	/*
+	 * If we have bottom, this will mark the ancestors of the
+	 * bottom commits we would reach while traversing as
+	 * uninteresting.
+	 */
+	if (prepare_revision_walk(sb->revs))
+		die(_("revision walk setup failed"));
+
+	if (sb->reverse && sb->revs->first_parent_only) {
+		struct commit *c = final_commit;
+
+		sb->revs->children.name = "children";
+		while (c->parents &&
+		       oidcmp(&c->object.oid, &sb->final->object.oid)) {
+			struct commit_list *l = xcalloc(1, sizeof(*l));
+
+			l->item = c;
+			if (add_decoration(&sb->revs->children,
+					   &c->parents->item->object, l))
+				die("BUG: not unique item in first-parent chain");
+			c = c->parents->item;
+		}
+
+		if (oidcmp(&c->object.oid, &sb->final->object.oid))
+			die(_("--reverse --first-parent together require range along first-parent chain"));
+	}
+
+	if (is_null_oid(&sb->final->object.oid)) {
+		o = sb->final->util;
+		sb->final_buf = xmemdupz(o->file.ptr, o->file.size);
+		sb->final_buf_size = o->file.size;
+	}
+	else {
+		o = get_origin(sb->final, path);
+		if (fill_blob_sha1_and_mode(o))
+			die(_("no such path %s in %s"), path, final_commit_name);
+
+		if (DIFF_OPT_TST(&sb->revs->diffopt, ALLOW_TEXTCONV) &&
+		    textconv_object(path, o->mode, &o->blob_oid, 1, (char **) &sb->final_buf,
+				    &sb->final_buf_size))
+			;
+		else
+			sb->final_buf = read_sha1_file(o->blob_oid.hash, &type,
+						       &sb->final_buf_size);
+
+		if (!sb->final_buf)
+			die(_("cannot read blob %s for path %s"),
+			    oid_to_hex(&o->blob_oid),
+			    path);
+	}
+	sb->num_read_blob++;
+	prepare_lines(sb);
+
+	if (orig)
+		*orig = o;
+}
+
+
+
+struct blame_entry *blame_entry_prepend(struct blame_entry *head,
+					long start, long end,
+					struct blame_origin *o)
+{
+	struct blame_entry *new_head = xcalloc(1, sizeof(struct blame_entry));
+	new_head->lno = start;
+	new_head->num_lines = end - start;
+	new_head->suspect = o;
+	new_head->s_lno = start;
+	new_head->next = head;
+	blame_origin_incref(o);
+	return new_head;
+}
diff --git a/blame.h b/blame.h
new file mode 100644
index 0000000000..a6c915c277
--- /dev/null
+++ b/blame.h
@@ -0,0 +1,175 @@
+#ifndef BLAME_H
+#define BLAME_H
+
+#include "cache.h"
+#include "commit.h"
+#include "xdiff-interface.h"
+#include "revision.h"
+#include "prio-queue.h"
+#include "diff.h"
+
+#define PICKAXE_BLAME_MOVE		01
+#define PICKAXE_BLAME_COPY		02
+#define PICKAXE_BLAME_COPY_HARDER	04
+#define PICKAXE_BLAME_COPY_HARDEST	010
+
+#define BLAME_DEFAULT_MOVE_SCORE	20
+#define BLAME_DEFAULT_COPY_SCORE	40
+
+/*
+ * One blob in a commit that is being suspected
+ */
+struct blame_origin {
+	int refcnt;
+	/* Record preceding blame record for this blob */
+	struct blame_origin *previous;
+	/* origins are put in a list linked via `next' hanging off the
+	 * corresponding commit's util field in order to make finding
+	 * them fast.  The presence in this chain does not count
+	 * towards the origin's reference count.  It is tempting to
+	 * let it count as long as the commit is pending examination,
+	 * but even under circumstances where the commit will be
+	 * present multiple times in the priority queue of unexamined
+	 * commits, processing the first instance will not leave any
+	 * work requiring the origin data for the second instance.  An
+	 * interspersed commit changing that would have to be
+	 * preexisting with a different ancestry and with the same
+	 * commit date in order to wedge itself between two instances
+	 * of the same commit in the priority queue _and_ produce
+	 * blame entries relevant for it.  While we don't want to let
+	 * us get tripped up by this case, it certainly does not seem
+	 * worth optimizing for.
+	 */
+	struct blame_origin *next;
+	struct commit *commit;
+	/* `suspects' contains blame entries that may be attributed to
+	 * this origin's commit or to parent commits.  When a commit
+	 * is being processed, all suspects will be moved, either by
+	 * assigning them to an origin in a different commit, or by
+	 * shipping them to the scoreboard's ent list because they
+	 * cannot be attributed to a different commit.
+	 */
+	struct blame_entry *suspects;
+	mmfile_t file;
+	struct object_id blob_oid;
+	unsigned mode;
+	/* guilty gets set when shipping any suspects to the final
+	 * blame list instead of other commits
+	 */
+	char guilty;
+	char path[FLEX_ARRAY];
+};
+
+/*
+ * Each group of lines is described by a blame_entry; it can be split
+ * as we pass blame to the parents.  They are arranged in linked lists
+ * kept as `suspects' of some unprocessed origin, or entered (when the
+ * blame origin has been finalized) into the scoreboard structure.
+ * While the scoreboard structure is only sorted at the end of
+ * processing (according to final image line number), the lists
+ * attached to an origin are sorted by the target line number.
+ */
+struct blame_entry {
+	struct blame_entry *next;
+
+	/* the first line of this group in the final image;
+	 * internally all line numbers are 0 based.
+	 */
+	int lno;
+
+	/* how many lines this group has */
+	int num_lines;
+
+	/* the commit that introduced this group into the final image */
+	struct blame_origin *suspect;
+
+	/* the line number of the first line of this group in the
+	 * suspect's file; internally all line numbers are 0 based.
+	 */
+	int s_lno;
+
+	/* how significant this entry is -- cached to avoid
+	 * scanning the lines over and over.
+	 */
+	unsigned score;
+};
+
+/*
+ * The current state of the blame assignment.
+ */
+struct blame_scoreboard {
+	/* the final commit (i.e. where we started digging from) */
+	struct commit *final;
+	/* Priority queue for commits with unassigned blame records */
+	struct prio_queue commits;
+	struct rev_info *revs;
+	const char *path;
+
+	/*
+	 * The contents in the final image.
+	 * Used by many functions to obtain contents of the nth line,
+	 * indexed with scoreboard.lineno[blame_entry.lno].
+	 */
+	const char *final_buf;
+	unsigned long final_buf_size;
+
+	/* linked list of blames */
+	struct blame_entry *ent;
+
+	/* look-up a line in the final buffer */
+	int num_lines;
+	int *lineno;
+
+	/* stats */
+	int num_read_blob;
+	int num_get_patch;
+	int num_commits;
+
+	/*
+	 * blame for a blame_entry with score lower than these thresholds
+	 * is not passed to the parent using move/copy logic.
+	 */
+	unsigned move_score;
+	unsigned copy_score;
+
+	/* use this file's contents as the final image */
+	const char *contents_from;
+
+	/* flags */
+	int reverse;
+	int show_root;
+	int xdl_opts;
+	int no_whole_file_rename;
+	int debug;
+
+	/* callbacks */
+	void(*on_sanity_fail)(struct blame_scoreboard *, int);
+	void(*found_guilty_entry)(struct blame_entry *, void *);
+
+	void *found_guilty_entry_data;
+};
+
+/*
+ * Origin is refcounted and usually we keep the blob contents to be
+ * reused.
+ */
+static inline struct blame_origin *blame_origin_incref(struct blame_origin *o)
+{
+	if (o)
+		o->refcnt++;
+	return o;
+}
+extern void blame_origin_decref(struct blame_origin *o);
+
+extern void blame_coalesce(struct blame_scoreboard *sb);
+extern void blame_sort_final(struct blame_scoreboard *sb);
+extern unsigned blame_entry_score(struct blame_scoreboard *sb, struct blame_entry *e);
+extern void assign_blame(struct blame_scoreboard *sb, int opt);
+extern const char *blame_nth_line(struct blame_scoreboard *sb, long lno);
+
+extern void init_scoreboard(struct blame_scoreboard *sb);
+extern void setup_scoreboard(struct blame_scoreboard *sb, const char *path, struct blame_origin **orig);
+
+extern struct blame_entry *blame_entry_prepend(struct blame_entry *head, long start, long end, struct blame_origin *o);
+
+#endif /* BLAME_H */
diff --git a/builtin.h b/builtin.h
index 9e4a89816d..498ac80d07 100644
--- a/builtin.h
+++ b/builtin.h
@@ -25,8 +25,6 @@ struct fmt_merge_msg_opts {
 extern int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 			 struct fmt_merge_msg_opts *);
 
-extern int textconv_object(const char *path, unsigned mode, const struct object_id *oid, int oid_valid, char **buf, unsigned long *buf_size);
-
 extern int is_builtin(const char *s);
 
 extern int cmd_add(int argc, const char **argv, const char *prefix);
diff --git a/builtin/blame.c b/builtin/blame.c
index 9cb9610115..d7a2df3b47 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -6,21 +6,13 @@
  */
 
 #include "cache.h"
-#include "refs.h"
 #include "builtin.h"
-#include "blob.h"
 #include "commit.h"
-#include "tag.h"
-#include "tree-walk.h"
 #include "diff.h"
-#include "diffcore.h"
 #include "revision.h"
 #include "quote.h"
-#include "xdiff-interface.h"
-#include "cache-tree.h"
 #include "string-list.h"
 #include "mailmap.h"
-#include "mergesort.h"
 #include "parse-options.h"
 #include "prio-queue.h"
 #include "utf8.h"
@@ -29,6 +21,7 @@
 #include "line-log.h"
 #include "dir.h"
 #include "progress.h"
+#include "blame.h"
 
 static char blame_usage[] = N_("git blame [<options>] [<rev-opts>] [<rev>] [--] <file>");
 
@@ -62,1497 +55,21 @@ static struct string_list mailmap = STRING_LIST_INIT_NODUP;
 #define DEBUG 0
 #endif
 
-/* stats */
-static int num_read_blob;
-static int num_get_patch;
-static int num_commits;
-
-#define PICKAXE_BLAME_MOVE		01
-#define PICKAXE_BLAME_COPY		02
-#define PICKAXE_BLAME_COPY_HARDER	04
-#define PICKAXE_BLAME_COPY_HARDEST	010
-
-/*
- * blame for a blame_entry with score lower than these thresholds
- * is not passed to the parent using move/copy logic.
- */
 static unsigned blame_move_score;
 static unsigned blame_copy_score;
-#define BLAME_DEFAULT_MOVE_SCORE	20
-#define BLAME_DEFAULT_COPY_SCORE	40
 
 /* Remember to update object flag allocation in object.h */
 #define METAINFO_SHOWN		(1u<<12)
 #define MORE_THAN_ONE_PATH	(1u<<13)
 
-/*
- * One blob in a commit that is being suspected
- */
-struct origin {
-	int refcnt;
-	/* Record preceding blame record for this blob */
-	struct origin *previous;
-	/* origins are put in a list linked via `next' hanging off the
-	 * corresponding commit's util field in order to make finding
-	 * them fast.  The presence in this chain does not count
-	 * towards the origin's reference count.  It is tempting to
-	 * let it count as long as the commit is pending examination,
-	 * but even under circumstances where the commit will be
-	 * present multiple times in the priority queue of unexamined
-	 * commits, processing the first instance will not leave any
-	 * work requiring the origin data for the second instance.  An
-	 * interspersed commit changing that would have to be
-	 * preexisting with a different ancestry and with the same
-	 * commit date in order to wedge itself between two instances
-	 * of the same commit in the priority queue _and_ produce
-	 * blame entries relevant for it.  While we don't want to let
-	 * us get tripped up by this case, it certainly does not seem
-	 * worth optimizing for.
-	 */
-	struct origin *next;
-	struct commit *commit;
-	/* `suspects' contains blame entries that may be attributed to
-	 * this origin's commit or to parent commits.  When a commit
-	 * is being processed, all suspects will be moved, either by
-	 * assigning them to an origin in a different commit, or by
-	 * shipping them to the scoreboard's ent list because they
-	 * cannot be attributed to a different commit.
-	 */
-	struct blame_entry *suspects;
-	mmfile_t file;
-	struct object_id blob_oid;
-	unsigned mode;
-	/* guilty gets set when shipping any suspects to the final
-	 * blame list instead of other commits
-	 */
-	char guilty;
-	char path[FLEX_ARRAY];
-};
-
 struct progress_info {
 	struct progress *progress;
 	int blamed_lines;
 };
 
-static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b,
-		      xdl_emit_hunk_consume_func_t hunk_func, void *cb_data)
-{
-	xpparam_t xpp = {0};
-	xdemitconf_t xecfg = {0};
-	xdemitcb_t ecb = {NULL};
-
-	xpp.flags = xdl_opts;
-	xecfg.hunk_func = hunk_func;
-	ecb.priv = cb_data;
-	return xdi_diff(file_a, file_b, &xpp, &xecfg, &ecb);
-}
-
-/*
- * Prepare diff_filespec and convert it using diff textconv API
- * if the textconv driver exists.
- * Return 1 if the conversion succeeds, 0 otherwise.
- */
-int textconv_object(const char *path,
-		    unsigned mode,
-		    const struct object_id *oid,
-		    int oid_valid,
-		    char **buf,
-		    unsigned long *buf_size)
-{
-	struct diff_filespec *df;
-	struct userdiff_driver *textconv;
-
-	df = alloc_filespec(path);
-	fill_filespec(df, oid->hash, oid_valid, mode);
-	textconv = get_textconv(df);
-	if (!textconv) {
-		free_filespec(df);
-		return 0;
-	}
-
-	*buf_size = fill_textconv(textconv, df, buf);
-	free_filespec(df);
-	return 1;
-}
-
-/*
- * Given an origin, prepare mmfile_t structure to be used by the
- * diff machinery
- */
-static void fill_origin_blob(struct diff_options *opt,
-			     struct origin *o, mmfile_t *file)
-{
-	if (!o->file.ptr) {
-		enum object_type type;
-		unsigned long file_size;
-
-		num_read_blob++;
-		if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV) &&
-		    textconv_object(o->path, o->mode, &o->blob_oid, 1, &file->ptr, &file_size))
-			;
-		else
-			file->ptr = read_sha1_file(o->blob_oid.hash, &type,
-						   &file_size);
-		file->size = file_size;
-
-		if (!file->ptr)
-			die("Cannot read blob %s for path %s",
-			    oid_to_hex(&o->blob_oid),
-			    o->path);
-		o->file = *file;
-	}
-	else
-		*file = o->file;
-}
-
-/*
- * Origin is refcounted and usually we keep the blob contents to be
- * reused.
- */
-static inline struct origin *origin_incref(struct origin *o)
-{
-	if (o)
-		o->refcnt++;
-	return o;
-}
-
-static void origin_decref(struct origin *o)
-{
-	if (o && --o->refcnt <= 0) {
-		struct origin *p, *l = NULL;
-		if (o->previous)
-			origin_decref(o->previous);
-		free(o->file.ptr);
-		/* Should be present exactly once in commit chain */
-		for (p = o->commit->util; p; l = p, p = p->next) {
-			if (p == o) {
-				if (l)
-					l->next = p->next;
-				else
-					o->commit->util = p->next;
-				free(o);
-				return;
-			}
-		}
-		die("internal error in blame::origin_decref");
-	}
-}
-
-static void drop_origin_blob(struct origin *o)
-{
-	if (o->file.ptr) {
-		free(o->file.ptr);
-		o->file.ptr = NULL;
-	}
-}
-
-/*
- * Each group of lines is described by a blame_entry; it can be split
- * as we pass blame to the parents.  They are arranged in linked lists
- * kept as `suspects' of some unprocessed origin, or entered (when the
- * blame origin has been finalized) into the scoreboard structure.
- * While the scoreboard structure is only sorted at the end of
- * processing (according to final image line number), the lists
- * attached to an origin are sorted by the target line number.
- */
-struct blame_entry {
-	struct blame_entry *next;
-
-	/* the first line of this group in the final image;
-	 * internally all line numbers are 0 based.
-	 */
-	int lno;
-
-	/* how many lines this group has */
-	int num_lines;
-
-	/* the commit that introduced this group into the final image */
-	struct origin *suspect;
-
-	/* the line number of the first line of this group in the
-	 * suspect's file; internally all line numbers are 0 based.
-	 */
-	int s_lno;
-
-	/* how significant this entry is -- cached to avoid
-	 * scanning the lines over and over.
-	 */
-	unsigned score;
-};
-
-/*
- * Any merge of blames happens on lists of blames that arrived via
- * different parents in a single suspect.  In this case, we want to
- * sort according to the suspect line numbers as opposed to the final
- * image line numbers.  The function body is somewhat longish because
- * it avoids unnecessary writes.
- */
-
-static struct blame_entry *blame_merge(struct blame_entry *list1,
-				       struct blame_entry *list2)
-{
-	struct blame_entry *p1 = list1, *p2 = list2,
-		**tail = &list1;
-
-	if (!p1)
-		return p2;
-	if (!p2)
-		return p1;
-
-	if (p1->s_lno <= p2->s_lno) {
-		do {
-			tail = &p1->next;
-			if ((p1 = *tail) == NULL) {
-				*tail = p2;
-				return list1;
-			}
-		} while (p1->s_lno <= p2->s_lno);
-	}
-	for (;;) {
-		*tail = p2;
-		do {
-			tail = &p2->next;
-			if ((p2 = *tail) == NULL)  {
-				*tail = p1;
-				return list1;
-			}
-		} while (p1->s_lno > p2->s_lno);
-		*tail = p1;
-		do {
-			tail = &p1->next;
-			if ((p1 = *tail) == NULL) {
-				*tail = p2;
-				return list1;
-			}
-		} while (p1->s_lno <= p2->s_lno);
-	}
-}
-
-static void *get_next_blame(const void *p)
-{
-	return ((struct blame_entry *)p)->next;
-}
-
-static void set_next_blame(void *p1, void *p2)
-{
-	((struct blame_entry *)p1)->next = p2;
-}
-
-/*
- * Final image line numbers are all different, so we don't need a
- * three-way comparison here.
- */
-
-static int compare_blame_final(const void *p1, const void *p2)
-{
-	return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno
-		? 1 : -1;
-}
-
-static int compare_blame_suspect(const void *p1, const void *p2)
-{
-	const struct blame_entry *s1 = p1, *s2 = p2;
-	/*
-	 * to allow for collating suspects, we sort according to the
-	 * respective pointer value as the primary sorting criterion.
-	 * The actual relation is pretty unimportant as long as it
-	 * establishes a total order.  Comparing as integers gives us
-	 * that.
-	 */
-	if (s1->suspect != s2->suspect)
-		return (intptr_t)s1->suspect > (intptr_t)s2->suspect ? 1 : -1;
-	if (s1->s_lno == s2->s_lno)
-		return 0;
-	return s1->s_lno > s2->s_lno ? 1 : -1;
-}
-
-static struct blame_entry *blame_sort(struct blame_entry *head,
-				      int (*compare_fn)(const void *, const void *))
-{
-	return llist_mergesort (head, get_next_blame, set_next_blame, compare_fn);
-}
-
-static int compare_commits_by_reverse_commit_date(const void *a,
-						  const void *b,
-						  void *c)
-{
-	return -compare_commits_by_commit_date(a, b, c);
-}
-
-/*
- * The current state of the blame assignment.
- */
-struct scoreboard {
-	/* the final commit (i.e. where we started digging from) */
-	struct commit *final;
-	/* Priority queue for commits with unassigned blame records */
-	struct prio_queue commits;
-	struct rev_info *revs;
-	const char *path;
-
-	/*
-	 * The contents in the final image.
-	 * Used by many functions to obtain contents of the nth line,
-	 * indexed with scoreboard.lineno[blame_entry.lno].
-	 */
-	const char *final_buf;
-	unsigned long final_buf_size;
-
-	/* linked list of blames */
-	struct blame_entry *ent;
-
-	/* look-up a line in the final buffer */
-	int num_lines;
-	int *lineno;
-};
-
-static void sanity_check_refcnt(struct scoreboard *);
-
-/*
- * If two blame entries that are next to each other came from
- * contiguous lines in the same origin (i.e. <commit, path> pair),
- * merge them together.
- */
-static void coalesce(struct scoreboard *sb)
-{
-	struct blame_entry *ent, *next;
-
-	for (ent = sb->ent; ent && (next = ent->next); ent = next) {
-		if (ent->suspect == next->suspect &&
-		    ent->s_lno + ent->num_lines == next->s_lno) {
-			ent->num_lines += next->num_lines;
-			ent->next = next->next;
-			origin_decref(next->suspect);
-			free(next);
-			ent->score = 0;
-			next = ent; /* again */
-		}
-	}
-
-	if (DEBUG) /* sanity */
-		sanity_check_refcnt(sb);
-}
-
-/*
- * Merge the given sorted list of blames into a preexisting origin.
- * If there were no previous blames to that commit, it is entered into
- * the commit priority queue of the score board.
- */
-
-static void queue_blames(struct scoreboard *sb, struct origin *porigin,
-			 struct blame_entry *sorted)
-{
-	if (porigin->suspects)
-		porigin->suspects = blame_merge(porigin->suspects, sorted);
-	else {
-		struct origin *o;
-		for (o = porigin->commit->util; o; o = o->next) {
-			if (o->suspects) {
-				porigin->suspects = sorted;
-				return;
-			}
-		}
-		porigin->suspects = sorted;
-		prio_queue_put(&sb->commits, porigin->commit);
-	}
-}
-
-/*
- * Given a commit and a path in it, create a new origin structure.
- * The callers that add blame to the scoreboard should use
- * get_origin() to obtain shared, refcounted copy instead of calling
- * this function directly.
- */
-static struct origin *make_origin(struct commit *commit, const char *path)
-{
-	struct origin *o;
-	FLEX_ALLOC_STR(o, path, path);
-	o->commit = commit;
-	o->refcnt = 1;
-	o->next = commit->util;
-	commit->util = o;
-	return o;
-}
-
-/*
- * Locate an existing origin or create a new one.
- * This moves the origin to front position in the commit util list.
- */
-static struct origin *get_origin(struct scoreboard *sb,
-				 struct commit *commit,
-				 const char *path)
-{
-	struct origin *o, *l;
-
-	for (o = commit->util, l = NULL; o; l = o, o = o->next) {
-		if (!strcmp(o->path, path)) {
-			/* bump to front */
-			if (l) {
-				l->next = o->next;
-				o->next = commit->util;
-				commit->util = o;
-			}
-			return origin_incref(o);
-		}
-	}
-	return make_origin(commit, path);
-}
-
-/*
- * Fill the blob_sha1 field of an origin if it hasn't, so that later
- * call to fill_origin_blob() can use it to locate the data.  blob_sha1
- * for an origin is also used to pass the blame for the entire file to
- * the parent to detect the case where a child's blob is identical to
- * that of its parent's.
- *
- * This also fills origin->mode for corresponding tree path.
- */
-static int fill_blob_sha1_and_mode(struct origin *origin)
-{
-	if (!is_null_oid(&origin->blob_oid))
-		return 0;
-	if (get_tree_entry(origin->commit->object.oid.hash,
-			   origin->path,
-			   origin->blob_oid.hash, &origin->mode))
-		goto error_out;
-	if (sha1_object_info(origin->blob_oid.hash, NULL) != OBJ_BLOB)
-		goto error_out;
-	return 0;
- error_out:
-	oidclr(&origin->blob_oid);
-	origin->mode = S_IFINVALID;
-	return -1;
-}
-
-/*
- * We have an origin -- check if the same path exists in the
- * parent and return an origin structure to represent it.
- */
-static struct origin *find_origin(struct scoreboard *sb,
-				  struct commit *parent,
-				  struct origin *origin)
-{
-	struct origin *porigin;
-	struct diff_options diff_opts;
-	const char *paths[2];
-
-	/* First check any existing origins */
-	for (porigin = parent->util; porigin; porigin = porigin->next)
-		if (!strcmp(porigin->path, origin->path)) {
-			/*
-			 * The same path between origin and its parent
-			 * without renaming -- the most common case.
-			 */
-			return origin_incref (porigin);
-		}
-
-	/* See if the origin->path is different between parent
-	 * and origin first.  Most of the time they are the
-	 * same and diff-tree is fairly efficient about this.
-	 */
-	diff_setup(&diff_opts);
-	DIFF_OPT_SET(&diff_opts, RECURSIVE);
-	diff_opts.detect_rename = 0;
-	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-	paths[0] = origin->path;
-	paths[1] = NULL;
-
-	parse_pathspec(&diff_opts.pathspec,
-		       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
-		       PATHSPEC_LITERAL_PATH, "", paths);
-	diff_setup_done(&diff_opts);
-
-	if (is_null_oid(&origin->commit->object.oid))
-		do_diff_cache(&parent->tree->object.oid, &diff_opts);
-	else
-		diff_tree_sha1(parent->tree->object.oid.hash,
-			       origin->commit->tree->object.oid.hash,
-			       "", &diff_opts);
-	diffcore_std(&diff_opts);
-
-	if (!diff_queued_diff.nr) {
-		/* The path is the same as parent */
-		porigin = get_origin(sb, parent, origin->path);
-		oidcpy(&porigin->blob_oid, &origin->blob_oid);
-		porigin->mode = origin->mode;
-	} else {
-		/*
-		 * Since origin->path is a pathspec, if the parent
-		 * commit had it as a directory, we will see a whole
-		 * bunch of deletion of files in the directory that we
-		 * do not care about.
-		 */
-		int i;
-		struct diff_filepair *p = NULL;
-		for (i = 0; i < diff_queued_diff.nr; i++) {
-			const char *name;
-			p = diff_queued_diff.queue[i];
-			name = p->one->path ? p->one->path : p->two->path;
-			if (!strcmp(name, origin->path))
-				break;
-		}
-		if (!p)
-			die("internal error in blame::find_origin");
-		switch (p->status) {
-		default:
-			die("internal error in blame::find_origin (%c)",
-			    p->status);
-		case 'M':
-			porigin = get_origin(sb, parent, origin->path);
-			oidcpy(&porigin->blob_oid, &p->one->oid);
-			porigin->mode = p->one->mode;
-			break;
-		case 'A':
-		case 'T':
-			/* Did not exist in parent, or type changed */
-			break;
-		}
-	}
-	diff_flush(&diff_opts);
-	clear_pathspec(&diff_opts.pathspec);
-	return porigin;
-}
-
-/*
- * We have an origin -- find the path that corresponds to it in its
- * parent and return an origin structure to represent it.
- */
-static struct origin *find_rename(struct scoreboard *sb,
-				  struct commit *parent,
-				  struct origin *origin)
-{
-	struct origin *porigin = NULL;
-	struct diff_options diff_opts;
-	int i;
-
-	diff_setup(&diff_opts);
-	DIFF_OPT_SET(&diff_opts, RECURSIVE);
-	diff_opts.detect_rename = DIFF_DETECT_RENAME;
-	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-	diff_opts.single_follow = origin->path;
-	diff_setup_done(&diff_opts);
-
-	if (is_null_oid(&origin->commit->object.oid))
-		do_diff_cache(&parent->tree->object.oid, &diff_opts);
-	else
-		diff_tree_sha1(parent->tree->object.oid.hash,
-			       origin->commit->tree->object.oid.hash,
-			       "", &diff_opts);
-	diffcore_std(&diff_opts);
-
-	for (i = 0; i < diff_queued_diff.nr; i++) {
-		struct diff_filepair *p = diff_queued_diff.queue[i];
-		if ((p->status == 'R' || p->status == 'C') &&
-		    !strcmp(p->two->path, origin->path)) {
-			porigin = get_origin(sb, parent, p->one->path);
-			oidcpy(&porigin->blob_oid, &p->one->oid);
-			porigin->mode = p->one->mode;
-			break;
-		}
-	}
-	diff_flush(&diff_opts);
-	clear_pathspec(&diff_opts.pathspec);
-	return porigin;
-}
-
-/*
- * Append a new blame entry to a given output queue.
- */
-static void add_blame_entry(struct blame_entry ***queue,
-			    const struct blame_entry *src)
-{
-	struct blame_entry *e = xmalloc(sizeof(*e));
-	memcpy(e, src, sizeof(*e));
-	origin_incref(e->suspect);
-
-	e->next = **queue;
-	**queue = e;
-	*queue = &e->next;
-}
-
-/*
- * src typically is on-stack; we want to copy the information in it to
- * a malloced blame_entry that gets added to the given queue.  The
- * origin of dst loses a refcnt.
- */
-static void dup_entry(struct blame_entry ***queue,
-		      struct blame_entry *dst, struct blame_entry *src)
-{
-	origin_incref(src->suspect);
-	origin_decref(dst->suspect);
-	memcpy(dst, src, sizeof(*src));
-	dst->next = **queue;
-	**queue = dst;
-	*queue = &dst->next;
-}
-
-static const char *nth_line(struct scoreboard *sb, long lno)
-{
-	return sb->final_buf + sb->lineno[lno];
-}
-
 static const char *nth_line_cb(void *data, long lno)
 {
-	return nth_line((struct scoreboard *)data, lno);
-}
-
-/*
- * It is known that lines between tlno to same came from parent, and e
- * has an overlap with that range.  it also is known that parent's
- * line plno corresponds to e's line tlno.
- *
- *                <---- e ----->
- *                   <------>
- *                   <------------>
- *             <------------>
- *             <------------------>
- *
- * Split e into potentially three parts; before this chunk, the chunk
- * to be blamed for the parent, and after that portion.
- */
-static void split_overlap(struct blame_entry *split,
-			  struct blame_entry *e,
-			  int tlno, int plno, int same,
-			  struct origin *parent)
-{
-	int chunk_end_lno;
-	memset(split, 0, sizeof(struct blame_entry [3]));
-
-	if (e->s_lno < tlno) {
-		/* there is a pre-chunk part not blamed on parent */
-		split[0].suspect = origin_incref(e->suspect);
-		split[0].lno = e->lno;
-		split[0].s_lno = e->s_lno;
-		split[0].num_lines = tlno - e->s_lno;
-		split[1].lno = e->lno + tlno - e->s_lno;
-		split[1].s_lno = plno;
-	}
-	else {
-		split[1].lno = e->lno;
-		split[1].s_lno = plno + (e->s_lno - tlno);
-	}
-
-	if (same < e->s_lno + e->num_lines) {
-		/* there is a post-chunk part not blamed on parent */
-		split[2].suspect = origin_incref(e->suspect);
-		split[2].lno = e->lno + (same - e->s_lno);
-		split[2].s_lno = e->s_lno + (same - e->s_lno);
-		split[2].num_lines = e->s_lno + e->num_lines - same;
-		chunk_end_lno = split[2].lno;
-	}
-	else
-		chunk_end_lno = e->lno + e->num_lines;
-	split[1].num_lines = chunk_end_lno - split[1].lno;
-
-	/*
-	 * if it turns out there is nothing to blame the parent for,
-	 * forget about the splitting.  !split[1].suspect signals this.
-	 */
-	if (split[1].num_lines < 1)
-		return;
-	split[1].suspect = origin_incref(parent);
-}
-
-/*
- * split_overlap() divided an existing blame e into up to three parts
- * in split.  Any assigned blame is moved to queue to
- * reflect the split.
- */
-static void split_blame(struct blame_entry ***blamed,
-			struct blame_entry ***unblamed,
-			struct blame_entry *split,
-			struct blame_entry *e)
-{
-	if (split[0].suspect && split[2].suspect) {
-		/* The first part (reuse storage for the existing entry e) */
-		dup_entry(unblamed, e, &split[0]);
-
-		/* The last part -- me */
-		add_blame_entry(unblamed, &split[2]);
-
-		/* ... and the middle part -- parent */
-		add_blame_entry(blamed, &split[1]);
-	}
-	else if (!split[0].suspect && !split[2].suspect)
-		/*
-		 * The parent covers the entire area; reuse storage for
-		 * e and replace it with the parent.
-		 */
-		dup_entry(blamed, e, &split[1]);
-	else if (split[0].suspect) {
-		/* me and then parent */
-		dup_entry(unblamed, e, &split[0]);
-		add_blame_entry(blamed, &split[1]);
-	}
-	else {
-		/* parent and then me */
-		dup_entry(blamed, e, &split[1]);
-		add_blame_entry(unblamed, &split[2]);
-	}
-}
-
-/*
- * After splitting the blame, the origins used by the
- * on-stack blame_entry should lose one refcnt each.
- */
-static void decref_split(struct blame_entry *split)
-{
-	int i;
-
-	for (i = 0; i < 3; i++)
-		origin_decref(split[i].suspect);
-}
-
-/*
- * reverse_blame reverses the list given in head, appending tail.
- * That allows us to build lists in reverse order, then reverse them
- * afterwards.  This can be faster than building the list in proper
- * order right away.  The reason is that building in proper order
- * requires writing a link in the _previous_ element, while building
- * in reverse order just requires placing the list head into the
- * _current_ element.
- */
-
-static struct blame_entry *reverse_blame(struct blame_entry *head,
-					 struct blame_entry *tail)
-{
-	while (head) {
-		struct blame_entry *next = head->next;
-		head->next = tail;
-		tail = head;
-		head = next;
-	}
-	return tail;
-}
-
-/*
- * Process one hunk from the patch between the current suspect for
- * blame_entry e and its parent.  This first blames any unfinished
- * entries before the chunk (which is where target and parent start
- * differing) on the parent, and then splits blame entries at the
- * start and at the end of the difference region.  Since use of -M and
- * -C options may lead to overlapping/duplicate source line number
- * ranges, all we can rely on from sorting/merging is the order of the
- * first suspect line number.
- */
-static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
-			int tlno, int offset, int same,
-			struct origin *parent)
-{
-	struct blame_entry *e = **srcq;
-	struct blame_entry *samep = NULL, *diffp = NULL;
-
-	while (e && e->s_lno < tlno) {
-		struct blame_entry *next = e->next;
-		/*
-		 * current record starts before differing portion.  If
-		 * it reaches into it, we need to split it up and
-		 * examine the second part separately.
-		 */
-		if (e->s_lno + e->num_lines > tlno) {
-			/* Move second half to a new record */
-			int len = tlno - e->s_lno;
-			struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
-			n->suspect = e->suspect;
-			n->lno = e->lno + len;
-			n->s_lno = e->s_lno + len;
-			n->num_lines = e->num_lines - len;
-			e->num_lines = len;
-			e->score = 0;
-			/* Push new record to diffp */
-			n->next = diffp;
-			diffp = n;
-		} else
-			origin_decref(e->suspect);
-		/* Pass blame for everything before the differing
-		 * chunk to the parent */
-		e->suspect = origin_incref(parent);
-		e->s_lno += offset;
-		e->next = samep;
-		samep = e;
-		e = next;
-	}
-	/*
-	 * As we don't know how much of a common stretch after this
-	 * diff will occur, the currently blamed parts are all that we
-	 * can assign to the parent for now.
-	 */
-
-	if (samep) {
-		**dstq = reverse_blame(samep, **dstq);
-		*dstq = &samep->next;
-	}
-	/*
-	 * Prepend the split off portions: everything after e starts
-	 * after the blameable portion.
-	 */
-	e = reverse_blame(diffp, e);
-
-	/*
-	 * Now retain records on the target while parts are different
-	 * from the parent.
-	 */
-	samep = NULL;
-	diffp = NULL;
-	while (e && e->s_lno < same) {
-		struct blame_entry *next = e->next;
-
-		/*
-		 * If current record extends into sameness, need to split.
-		 */
-		if (e->s_lno + e->num_lines > same) {
-			/*
-			 * Move second half to a new record to be
-			 * processed by later chunks
-			 */
-			int len = same - e->s_lno;
-			struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
-			n->suspect = origin_incref(e->suspect);
-			n->lno = e->lno + len;
-			n->s_lno = e->s_lno + len;
-			n->num_lines = e->num_lines - len;
-			e->num_lines = len;
-			e->score = 0;
-			/* Push new record to samep */
-			n->next = samep;
-			samep = n;
-		}
-		e->next = diffp;
-		diffp = e;
-		e = next;
-	}
-	**srcq = reverse_blame(diffp, reverse_blame(samep, e));
-	/* Move across elements that are in the unblamable portion */
-	if (diffp)
-		*srcq = &diffp->next;
-}
-
-struct blame_chunk_cb_data {
-	struct origin *parent;
-	long offset;
-	struct blame_entry **dstq;
-	struct blame_entry **srcq;
-};
-
-/* diff chunks are from parent to target */
-static int blame_chunk_cb(long start_a, long count_a,
-			  long start_b, long count_b, void *data)
-{
-	struct blame_chunk_cb_data *d = data;
-	if (start_a - start_b != d->offset)
-		die("internal error in blame::blame_chunk_cb");
-	blame_chunk(&d->dstq, &d->srcq, start_b, start_a - start_b,
-		    start_b + count_b, d->parent);
-	d->offset = start_a + count_a - (start_b + count_b);
-	return 0;
-}
-
-/*
- * We are looking at the origin 'target' and aiming to pass blame
- * for the lines it is suspected to its parent.  Run diff to find
- * which lines came from parent and pass blame for them.
- */
-static void pass_blame_to_parent(struct scoreboard *sb,
-				 struct origin *target,
-				 struct origin *parent)
-{
-	mmfile_t file_p, file_o;
-	struct blame_chunk_cb_data d;
-	struct blame_entry *newdest = NULL;
-
-	if (!target->suspects)
-		return; /* nothing remains for this target */
-
-	d.parent = parent;
-	d.offset = 0;
-	d.dstq = &newdest; d.srcq = &target->suspects;
-
-	fill_origin_blob(&sb->revs->diffopt, parent, &file_p);
-	fill_origin_blob(&sb->revs->diffopt, target, &file_o);
-	num_get_patch++;
-
-	if (diff_hunks(&file_p, &file_o, blame_chunk_cb, &d))
-		die("unable to generate diff (%s -> %s)",
-		    oid_to_hex(&parent->commit->object.oid),
-		    oid_to_hex(&target->commit->object.oid));
-	/* The rest are the same as the parent */
-	blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, parent);
-	*d.dstq = NULL;
-	queue_blames(sb, parent, newdest);
-
-	return;
-}
-
-/*
- * The lines in blame_entry after splitting blames many times can become
- * very small and trivial, and at some point it becomes pointless to
- * blame the parents.  E.g. "\t\t}\n\t}\n\n" appears everywhere in any
- * ordinary C program, and it is not worth to say it was copied from
- * totally unrelated file in the parent.
- *
- * Compute how trivial the lines in the blame_entry are.
- */
-static unsigned ent_score(struct scoreboard *sb, struct blame_entry *e)
-{
-	unsigned score;
-	const char *cp, *ep;
-
-	if (e->score)
-		return e->score;
-
-	score = 1;
-	cp = nth_line(sb, e->lno);
-	ep = nth_line(sb, e->lno + e->num_lines);
-	while (cp < ep) {
-		unsigned ch = *((unsigned char *)cp);
-		if (isalnum(ch))
-			score++;
-		cp++;
-	}
-	e->score = score;
-	return score;
-}
-
-/*
- * best_so_far[] and this[] are both a split of an existing blame_entry
- * that passes blame to the parent.  Maintain best_so_far the best split
- * so far, by comparing this and best_so_far and copying this into
- * bst_so_far as needed.
- */
-static void copy_split_if_better(struct scoreboard *sb,
-				 struct blame_entry *best_so_far,
-				 struct blame_entry *this)
-{
-	int i;
-
-	if (!this[1].suspect)
-		return;
-	if (best_so_far[1].suspect) {
-		if (ent_score(sb, &this[1]) < ent_score(sb, &best_so_far[1]))
-			return;
-	}
-
-	for (i = 0; i < 3; i++)
-		origin_incref(this[i].suspect);
-	decref_split(best_so_far);
-	memcpy(best_so_far, this, sizeof(struct blame_entry [3]));
-}
-
-/*
- * We are looking at a part of the final image represented by
- * ent (tlno and same are offset by ent->s_lno).
- * tlno is where we are looking at in the final image.
- * up to (but not including) same match preimage.
- * plno is where we are looking at in the preimage.
- *
- * <-------------- final image ---------------------->
- *       <------ent------>
- *         ^tlno ^same
- *    <---------preimage----->
- *         ^plno
- *
- * All line numbers are 0-based.
- */
-static void handle_split(struct scoreboard *sb,
-			 struct blame_entry *ent,
-			 int tlno, int plno, int same,
-			 struct origin *parent,
-			 struct blame_entry *split)
-{
-	if (ent->num_lines <= tlno)
-		return;
-	if (tlno < same) {
-		struct blame_entry this[3];
-		tlno += ent->s_lno;
-		same += ent->s_lno;
-		split_overlap(this, ent, tlno, plno, same, parent);
-		copy_split_if_better(sb, split, this);
-		decref_split(this);
-	}
-}
-
-struct handle_split_cb_data {
-	struct scoreboard *sb;
-	struct blame_entry *ent;
-	struct origin *parent;
-	struct blame_entry *split;
-	long plno;
-	long tlno;
-};
-
-static int handle_split_cb(long start_a, long count_a,
-			   long start_b, long count_b, void *data)
-{
-	struct handle_split_cb_data *d = data;
-	handle_split(d->sb, d->ent, d->tlno, d->plno, start_b, d->parent,
-		     d->split);
-	d->plno = start_a + count_a;
-	d->tlno = start_b + count_b;
-	return 0;
-}
-
-/*
- * Find the lines from parent that are the same as ent so that
- * we can pass blames to it.  file_p has the blob contents for
- * the parent.
- */
-static void find_copy_in_blob(struct scoreboard *sb,
-			      struct blame_entry *ent,
-			      struct origin *parent,
-			      struct blame_entry *split,
-			      mmfile_t *file_p)
-{
-	const char *cp;
-	mmfile_t file_o;
-	struct handle_split_cb_data d;
-
-	memset(&d, 0, sizeof(d));
-	d.sb = sb; d.ent = ent; d.parent = parent; d.split = split;
-	/*
-	 * Prepare mmfile that contains only the lines in ent.
-	 */
-	cp = nth_line(sb, ent->lno);
-	file_o.ptr = (char *) cp;
-	file_o.size = nth_line(sb, ent->lno + ent->num_lines) - cp;
-
-	/*
-	 * file_o is a part of final image we are annotating.
-	 * file_p partially may match that image.
-	 */
-	memset(split, 0, sizeof(struct blame_entry [3]));
-	if (diff_hunks(file_p, &file_o, handle_split_cb, &d))
-		die("unable to generate diff (%s)",
-		    oid_to_hex(&parent->commit->object.oid));
-	/* remainder, if any, all match the preimage */
-	handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
-}
-
-/* Move all blame entries from list *source that have a score smaller
- * than score_min to the front of list *small.
- * Returns a pointer to the link pointing to the old head of the small list.
- */
-
-static struct blame_entry **filter_small(struct scoreboard *sb,
-					 struct blame_entry **small,
-					 struct blame_entry **source,
-					 unsigned score_min)
-{
-	struct blame_entry *p = *source;
-	struct blame_entry *oldsmall = *small;
-	while (p) {
-		if (ent_score(sb, p) <= score_min) {
-			*small = p;
-			small = &p->next;
-			p = *small;
-		} else {
-			*source = p;
-			source = &p->next;
-			p = *source;
-		}
-	}
-	*small = oldsmall;
-	*source = NULL;
-	return small;
-}
-
-/*
- * See if lines currently target is suspected for can be attributed to
- * parent.
- */
-static void find_move_in_parent(struct scoreboard *sb,
-				struct blame_entry ***blamed,
-				struct blame_entry **toosmall,
-				struct origin *target,
-				struct origin *parent)
-{
-	struct blame_entry *e, split[3];
-	struct blame_entry *unblamed = target->suspects;
-	struct blame_entry *leftover = NULL;
-	mmfile_t file_p;
-
-	if (!unblamed)
-		return; /* nothing remains for this target */
-
-	fill_origin_blob(&sb->revs->diffopt, parent, &file_p);
-	if (!file_p.ptr)
-		return;
-
-	/* At each iteration, unblamed has a NULL-terminated list of
-	 * entries that have not yet been tested for blame.  leftover
-	 * contains the reversed list of entries that have been tested
-	 * without being assignable to the parent.
-	 */
-	do {
-		struct blame_entry **unblamedtail = &unblamed;
-		struct blame_entry *next;
-		for (e = unblamed; e; e = next) {
-			next = e->next;
-			find_copy_in_blob(sb, e, parent, split, &file_p);
-			if (split[1].suspect &&
-			    blame_move_score < ent_score(sb, &split[1])) {
-				split_blame(blamed, &unblamedtail, split, e);
-			} else {
-				e->next = leftover;
-				leftover = e;
-			}
-			decref_split(split);
-		}
-		*unblamedtail = NULL;
-		toosmall = filter_small(sb, toosmall, &unblamed, blame_move_score);
-	} while (unblamed);
-	target->suspects = reverse_blame(leftover, NULL);
-}
-
-struct blame_list {
-	struct blame_entry *ent;
-	struct blame_entry split[3];
-};
-
-/*
- * Count the number of entries the target is suspected for,
- * and prepare a list of entry and the best split.
- */
-static struct blame_list *setup_blame_list(struct blame_entry *unblamed,
-					   int *num_ents_p)
-{
-	struct blame_entry *e;
-	int num_ents, i;
-	struct blame_list *blame_list = NULL;
-
-	for (e = unblamed, num_ents = 0; e; e = e->next)
-		num_ents++;
-	if (num_ents) {
-		blame_list = xcalloc(num_ents, sizeof(struct blame_list));
-		for (e = unblamed, i = 0; e; e = e->next)
-			blame_list[i++].ent = e;
-	}
-	*num_ents_p = num_ents;
-	return blame_list;
-}
-
-/*
- * For lines target is suspected for, see if we can find code movement
- * across file boundary from the parent commit.  porigin is the path
- * in the parent we already tried.
- */
-static void find_copy_in_parent(struct scoreboard *sb,
-				struct blame_entry ***blamed,
-				struct blame_entry **toosmall,
-				struct origin *target,
-				struct commit *parent,
-				struct origin *porigin,
-				int opt)
-{
-	struct diff_options diff_opts;
-	int i, j;
-	struct blame_list *blame_list;
-	int num_ents;
-	struct blame_entry *unblamed = target->suspects;
-	struct blame_entry *leftover = NULL;
-
-	if (!unblamed)
-		return; /* nothing remains for this target */
-
-	diff_setup(&diff_opts);
-	DIFF_OPT_SET(&diff_opts, RECURSIVE);
-	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-
-	diff_setup_done(&diff_opts);
-
-	/* Try "find copies harder" on new path if requested;
-	 * we do not want to use diffcore_rename() actually to
-	 * match things up; find_copies_harder is set only to
-	 * force diff_tree_sha1() to feed all filepairs to diff_queue,
-	 * and this code needs to be after diff_setup_done(), which
-	 * usually makes find-copies-harder imply copy detection.
-	 */
-	if ((opt & PICKAXE_BLAME_COPY_HARDEST)
-	    || ((opt & PICKAXE_BLAME_COPY_HARDER)
-		&& (!porigin || strcmp(target->path, porigin->path))))
-		DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
-
-	if (is_null_oid(&target->commit->object.oid))
-		do_diff_cache(&parent->tree->object.oid, &diff_opts);
-	else
-		diff_tree_sha1(parent->tree->object.oid.hash,
-			       target->commit->tree->object.oid.hash,
-			       "", &diff_opts);
-
-	if (!DIFF_OPT_TST(&diff_opts, FIND_COPIES_HARDER))
-		diffcore_std(&diff_opts);
-
-	do {
-		struct blame_entry **unblamedtail = &unblamed;
-		blame_list = setup_blame_list(unblamed, &num_ents);
-
-		for (i = 0; i < diff_queued_diff.nr; i++) {
-			struct diff_filepair *p = diff_queued_diff.queue[i];
-			struct origin *norigin;
-			mmfile_t file_p;
-			struct blame_entry this[3];
-
-			if (!DIFF_FILE_VALID(p->one))
-				continue; /* does not exist in parent */
-			if (S_ISGITLINK(p->one->mode))
-				continue; /* ignore git links */
-			if (porigin && !strcmp(p->one->path, porigin->path))
-				/* find_move already dealt with this path */
-				continue;
-
-			norigin = get_origin(sb, parent, p->one->path);
-			oidcpy(&norigin->blob_oid, &p->one->oid);
-			norigin->mode = p->one->mode;
-			fill_origin_blob(&sb->revs->diffopt, norigin, &file_p);
-			if (!file_p.ptr)
-				continue;
-
-			for (j = 0; j < num_ents; j++) {
-				find_copy_in_blob(sb, blame_list[j].ent,
-						  norigin, this, &file_p);
-				copy_split_if_better(sb, blame_list[j].split,
-						     this);
-				decref_split(this);
-			}
-			origin_decref(norigin);
-		}
-
-		for (j = 0; j < num_ents; j++) {
-			struct blame_entry *split = blame_list[j].split;
-			if (split[1].suspect &&
-			    blame_copy_score < ent_score(sb, &split[1])) {
-				split_blame(blamed, &unblamedtail, split,
-					    blame_list[j].ent);
-			} else {
-				blame_list[j].ent->next = leftover;
-				leftover = blame_list[j].ent;
-			}
-			decref_split(split);
-		}
-		free(blame_list);
-		*unblamedtail = NULL;
-		toosmall = filter_small(sb, toosmall, &unblamed, blame_copy_score);
-	} while (unblamed);
-	target->suspects = reverse_blame(leftover, NULL);
-	diff_flush(&diff_opts);
-	clear_pathspec(&diff_opts.pathspec);
-}
-
-/*
- * The blobs of origin and porigin exactly match, so everything
- * origin is suspected for can be blamed on the parent.
- */
-static void pass_whole_blame(struct scoreboard *sb,
-			     struct origin *origin, struct origin *porigin)
-{
-	struct blame_entry *e, *suspects;
-
-	if (!porigin->file.ptr && origin->file.ptr) {
-		/* Steal its file */
-		porigin->file = origin->file;
-		origin->file.ptr = NULL;
-	}
-	suspects = origin->suspects;
-	origin->suspects = NULL;
-	for (e = suspects; e; e = e->next) {
-		origin_incref(porigin);
-		origin_decref(e->suspect);
-		e->suspect = porigin;
-	}
-	queue_blames(sb, porigin, suspects);
-}
-
-/*
- * We pass blame from the current commit to its parents.  We keep saying
- * "parent" (and "porigin"), but what we mean is to find scapegoat to
- * exonerate ourselves.
- */
-static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit)
-{
-	if (!reverse) {
-		if (revs->first_parent_only &&
-		    commit->parents &&
-		    commit->parents->next) {
-			free_commit_list(commit->parents->next);
-			commit->parents->next = NULL;
-		}
-		return commit->parents;
-	}
-	return lookup_decoration(&revs->children, &commit->object);
-}
-
-static int num_scapegoats(struct rev_info *revs, struct commit *commit)
-{
-	struct commit_list *l = first_scapegoat(revs, commit);
-	return commit_list_count(l);
-}
-
-/* Distribute collected unsorted blames to the respected sorted lists
- * in the various origins.
- */
-static void distribute_blame(struct scoreboard *sb, struct blame_entry *blamed)
-{
-	blamed = blame_sort(blamed, compare_blame_suspect);
-	while (blamed)
-	{
-		struct origin *porigin = blamed->suspect;
-		struct blame_entry *suspects = NULL;
-		do {
-			struct blame_entry *next = blamed->next;
-			blamed->next = suspects;
-			suspects = blamed;
-			blamed = next;
-		} while (blamed && blamed->suspect == porigin);
-		suspects = reverse_blame(suspects, NULL);
-		queue_blames(sb, porigin, suspects);
-	}
-}
-
-#define MAXSG 16
-
-static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
-{
-	struct rev_info *revs = sb->revs;
-	int i, pass, num_sg;
-	struct commit *commit = origin->commit;
-	struct commit_list *sg;
-	struct origin *sg_buf[MAXSG];
-	struct origin *porigin, **sg_origin = sg_buf;
-	struct blame_entry *toosmall = NULL;
-	struct blame_entry *blames, **blametail = &blames;
-
-	num_sg = num_scapegoats(revs, commit);
-	if (!num_sg)
-		goto finish;
-	else if (num_sg < ARRAY_SIZE(sg_buf))
-		memset(sg_buf, 0, sizeof(sg_buf));
-	else
-		sg_origin = xcalloc(num_sg, sizeof(*sg_origin));
-
-	/*
-	 * The first pass looks for unrenamed path to optimize for
-	 * common cases, then we look for renames in the second pass.
-	 */
-	for (pass = 0; pass < 2 - no_whole_file_rename; pass++) {
-		struct origin *(*find)(struct scoreboard *,
-				       struct commit *, struct origin *);
-		find = pass ? find_rename : find_origin;
-
-		for (i = 0, sg = first_scapegoat(revs, commit);
-		     i < num_sg && sg;
-		     sg = sg->next, i++) {
-			struct commit *p = sg->item;
-			int j, same;
-
-			if (sg_origin[i])
-				continue;
-			if (parse_commit(p))
-				continue;
-			porigin = find(sb, p, origin);
-			if (!porigin)
-				continue;
-			if (!oidcmp(&porigin->blob_oid, &origin->blob_oid)) {
-				pass_whole_blame(sb, origin, porigin);
-				origin_decref(porigin);
-				goto finish;
-			}
-			for (j = same = 0; j < i; j++)
-				if (sg_origin[j] &&
-				    !oidcmp(&sg_origin[j]->blob_oid, &porigin->blob_oid)) {
-					same = 1;
-					break;
-				}
-			if (!same)
-				sg_origin[i] = porigin;
-			else
-				origin_decref(porigin);
-		}
-	}
-
-	num_commits++;
-	for (i = 0, sg = first_scapegoat(revs, commit);
-	     i < num_sg && sg;
-	     sg = sg->next, i++) {
-		struct origin *porigin = sg_origin[i];
-		if (!porigin)
-			continue;
-		if (!origin->previous) {
-			origin_incref(porigin);
-			origin->previous = porigin;
-		}
-		pass_blame_to_parent(sb, origin, porigin);
-		if (!origin->suspects)
-			goto finish;
-	}
-
-	/*
-	 * Optionally find moves in parents' files.
-	 */
-	if (opt & PICKAXE_BLAME_MOVE) {
-		filter_small(sb, &toosmall, &origin->suspects, blame_move_score);
-		if (origin->suspects) {
-			for (i = 0, sg = first_scapegoat(revs, commit);
-			     i < num_sg && sg;
-			     sg = sg->next, i++) {
-				struct origin *porigin = sg_origin[i];
-				if (!porigin)
-					continue;
-				find_move_in_parent(sb, &blametail, &toosmall, origin, porigin);
-				if (!origin->suspects)
-					break;
-			}
-		}
-	}
-
-	/*
-	 * Optionally find copies from parents' files.
-	 */
-	if (opt & PICKAXE_BLAME_COPY) {
-		if (blame_copy_score > blame_move_score)
-			filter_small(sb, &toosmall, &origin->suspects, blame_copy_score);
-		else if (blame_copy_score < blame_move_score) {
-			origin->suspects = blame_merge(origin->suspects, toosmall);
-			toosmall = NULL;
-			filter_small(sb, &toosmall, &origin->suspects, blame_copy_score);
-		}
-		if (!origin->suspects)
-			goto finish;
-
-		for (i = 0, sg = first_scapegoat(revs, commit);
-		     i < num_sg && sg;
-		     sg = sg->next, i++) {
-			struct origin *porigin = sg_origin[i];
-			find_copy_in_parent(sb, &blametail, &toosmall,
-					    origin, sg->item, porigin, opt);
-			if (!origin->suspects)
-				goto finish;
-		}
-	}
-
-finish:
-	*blametail = NULL;
-	distribute_blame(sb, blames);
-	/*
-	 * prepend toosmall to origin->suspects
-	 *
-	 * There is no point in sorting: this ends up on a big
-	 * unsorted list in the caller anyway.
-	 */
-	if (toosmall) {
-		struct blame_entry **tail = &toosmall;
-		while (*tail)
-			tail = &(*tail)->next;
-		*tail = origin->suspects;
-		origin->suspects = toosmall;
-	}
-	for (i = 0; i < num_sg; i++) {
-		if (sg_origin[i]) {
-			drop_origin_blob(sg_origin[i]);
-			origin_decref(sg_origin[i]);
-		}
-	}
-	drop_origin_blob(origin);
-	if (sg_buf != sg_origin)
-		free(sg_origin);
+	return blame_nth_line((struct blame_scoreboard *)data, lno);
 }
 
 /*
@@ -1699,10 +216,10 @@ static void get_commit_info(struct commit *commit,
  * To allow LF and other nonportable characters in pathnames,
  * they are c-style quoted as needed.
  */
-static void write_filename_info(struct origin *suspect)
+static void write_filename_info(struct blame_origin *suspect)
 {
 	if (suspect->previous) {
-		struct origin *prev = suspect->previous;
+		struct blame_origin *prev = suspect->previous;
 		printf("previous %s ", oid_to_hex(&prev->commit->object.oid));
 		write_name_quoted(prev->path, stdout, '\n');
 	}
@@ -1716,7 +233,7 @@ static void write_filename_info(struct origin *suspect)
  * the first time each commit appears in the output (unless the
  * user has specifically asked for us to repeat).
  */
-static int emit_one_suspect_detail(struct origin *suspect, int repeat)
+static int emit_one_suspect_detail(struct blame_origin *suspect, int repeat)
 {
 	struct commit_info ci;
 
@@ -1746,11 +263,12 @@ static int emit_one_suspect_detail(struct origin *suspect, int repeat)
  * The blame_entry is found to be guilty for the range.
  * Show it in incremental output.
  */
-static void found_guilty_entry(struct blame_entry *ent,
-			   struct progress_info *pi)
+static void found_guilty_entry(struct blame_entry *ent, void *data)
 {
+	struct progress_info *pi = (struct progress_info *)data;
+
 	if (incremental) {
-		struct origin *suspect = ent->suspect;
+		struct blame_origin *suspect = ent->suspect;
 
 		printf("%s %d %d %d\n",
 		       oid_to_hex(&suspect->commit->object.oid),
@@ -1763,80 +281,6 @@ static void found_guilty_entry(struct blame_entry *ent,
 	display_progress(pi->progress, pi->blamed_lines);
 }
 
-/*
- * The main loop -- while we have blobs with lines whose true origin
- * is still unknown, pick one blob, and allow its lines to pass blames
- * to its parents. */
-static void assign_blame(struct scoreboard *sb, int opt)
-{
-	struct rev_info *revs = sb->revs;
-	struct commit *commit = prio_queue_get(&sb->commits);
-	struct progress_info pi = { NULL, 0 };
-
-	if (show_progress)
-		pi.progress = start_progress_delay(_("Blaming lines"),
-						   sb->num_lines, 50, 1);
-
-	while (commit) {
-		struct blame_entry *ent;
-		struct origin *suspect = commit->util;
-
-		/* find one suspect to break down */
-		while (suspect && !suspect->suspects)
-			suspect = suspect->next;
-
-		if (!suspect) {
-			commit = prio_queue_get(&sb->commits);
-			continue;
-		}
-
-		assert(commit == suspect->commit);
-
-		/*
-		 * We will use this suspect later in the loop,
-		 * so hold onto it in the meantime.
-		 */
-		origin_incref(suspect);
-		parse_commit(commit);
-		if (reverse ||
-		    (!(commit->object.flags & UNINTERESTING) &&
-		     !(revs->max_age != -1 && commit->date < revs->max_age)))
-			pass_blame(sb, suspect, opt);
-		else {
-			commit->object.flags |= UNINTERESTING;
-			if (commit->object.parsed)
-				mark_parents_uninteresting(commit);
-		}
-		/* treat root commit as boundary */
-		if (!commit->parents && !show_root)
-			commit->object.flags |= UNINTERESTING;
-
-		/* Take responsibility for the remaining entries */
-		ent = suspect->suspects;
-		if (ent) {
-			suspect->guilty = 1;
-			for (;;) {
-				struct blame_entry *next = ent->next;
-				found_guilty_entry(ent, &pi);
-				if (next) {
-					ent = next;
-					continue;
-				}
-				ent->next = sb->ent;
-				sb->ent = suspect->suspects;
-				suspect->suspects = NULL;
-				break;
-			}
-		}
-		origin_decref(suspect);
-
-		if (DEBUG) /* sanity */
-			sanity_check_refcnt(sb);
-	}
-
-	stop_progress(&pi.progress);
-}
-
 static const char *format_time(timestamp_t time, const char *tz_str,
 			       int show_raw_time)
 {
@@ -1876,20 +320,20 @@ static const char *format_time(timestamp_t time, const char *tz_str,
 #define OUTPUT_SHOW_EMAIL	0400
 #define OUTPUT_LINE_PORCELAIN 01000
 
-static void emit_porcelain_details(struct origin *suspect, int repeat)
+static void emit_porcelain_details(struct blame_origin *suspect, int repeat)
 {
 	if (emit_one_suspect_detail(suspect, repeat) ||
 	    (suspect->commit->object.flags & MORE_THAN_ONE_PATH))
 		write_filename_info(suspect);
 }
 
-static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent,
+static void emit_porcelain(struct blame_scoreboard *sb, struct blame_entry *ent,
 			   int opt)
 {
 	int repeat = opt & OUTPUT_LINE_PORCELAIN;
 	int cnt;
 	const char *cp;
-	struct origin *suspect = ent->suspect;
+	struct blame_origin *suspect = ent->suspect;
 	char hex[GIT_MAX_HEXSZ + 1];
 
 	oid_to_hex_r(hex, &suspect->commit->object.oid);
@@ -1900,7 +344,7 @@ static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent,
 	       ent->num_lines);
 	emit_porcelain_details(suspect, repeat);
 
-	cp = nth_line(sb, ent->lno);
+	cp = blame_nth_line(sb, ent->lno);
 	for (cnt = 0; cnt < ent->num_lines; cnt++) {
 		char ch;
 		if (cnt) {
@@ -1922,11 +366,11 @@ static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent,
 		putchar('\n');
 }
 
-static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
+static void emit_other(struct blame_scoreboard *sb, struct blame_entry *ent, int opt)
 {
 	int cnt;
 	const char *cp;
-	struct origin *suspect = ent->suspect;
+	struct blame_origin *suspect = ent->suspect;
 	struct commit_info ci;
 	char hex[GIT_MAX_HEXSZ + 1];
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
@@ -1934,7 +378,7 @@ static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
 	get_commit_info(suspect->commit, &ci, 1);
 	oid_to_hex_r(hex, &suspect->commit->object.oid);
 
-	cp = nth_line(sb, ent->lno);
+	cp = blame_nth_line(sb, ent->lno);
 	for (cnt = 0; cnt < ent->num_lines; cnt++) {
 		char ch;
 		int length = (opt & OUTPUT_LONG_OBJECT_NAME) ? GIT_SHA1_HEXSZ : abbrev;
@@ -2001,14 +445,14 @@ static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
 	commit_info_destroy(&ci);
 }
 
-static void output(struct scoreboard *sb, int option)
+static void output(struct blame_scoreboard *sb, int option)
 {
 	struct blame_entry *ent;
 
 	if (option & OUTPUT_PORCELAIN) {
 		for (ent = sb->ent; ent; ent = ent->next) {
 			int count = 0;
-			struct origin *suspect;
+			struct blame_origin *suspect;
 			struct commit *commit = ent->suspect->commit;
 			if (commit->object.flags & MORE_THAN_ONE_PATH)
 				continue;
@@ -2030,40 +474,6 @@ static void output(struct scoreboard *sb, int option)
 	}
 }
 
-static const char *get_next_line(const char *start, const char *end)
-{
-	const char *nl = memchr(start, '\n', end - start);
-	return nl ? nl + 1 : end;
-}
-
-/*
- * To allow quick access to the contents of nth line in the
- * final image, prepare an index in the scoreboard.
- */
-static int prepare_lines(struct scoreboard *sb)
-{
-	const char *buf = sb->final_buf;
-	unsigned long len = sb->final_buf_size;
-	const char *end = buf + len;
-	const char *p;
-	int *lineno;
-	int num = 0;
-
-	for (p = buf; p < end; p = get_next_line(p, end))
-		num++;
-
-	ALLOC_ARRAY(sb->lineno, num + 1);
-	lineno = sb->lineno;
-
-	for (p = buf; p < end; p = get_next_line(p, end))
-		*lineno++ = p - buf;
-
-	*lineno = len;
-
-	sb->num_lines = num;
-	return sb->num_lines;
-}
-
 /*
  * Add phony grafts for use with -S; this is primarily to
  * support git's cvsserver that wants to give a linear history
@@ -2086,7 +496,7 @@ static int read_ancestry(const char *graft_file)
 	return 0;
 }
 
-static int update_auto_abbrev(int auto_abbrev, struct origin *suspect)
+static int update_auto_abbrev(int auto_abbrev, struct blame_origin *suspect)
 {
 	const char *uniq = find_unique_abbrev(suspect->commit->object.oid.hash,
 					      auto_abbrev);
@@ -2100,7 +510,7 @@ static int update_auto_abbrev(int auto_abbrev, struct origin *suspect)
  * How many columns do we need to show line numbers, authors,
  * and filenames?
  */
-static void find_alignment(struct scoreboard *sb, int *option)
+static void find_alignment(struct blame_scoreboard *sb, int *option)
 {
 	int longest_src_lines = 0;
 	int longest_dst_lines = 0;
@@ -2110,7 +520,7 @@ static void find_alignment(struct scoreboard *sb, int *option)
 	int auto_abbrev = DEFAULT_ABBREV;
 
 	for (e = sb->ent; e; e = e->next) {
-		struct origin *suspect = e->suspect;
+		struct blame_origin *suspect = e->suspect;
 		int num;
 
 		if (compute_auto_abbrev)
@@ -2138,8 +548,8 @@ static void find_alignment(struct scoreboard *sb, int *option)
 		num = e->lno + e->num_lines;
 		if (longest_dst_lines < num)
 			longest_dst_lines = num;
-		if (largest_score < ent_score(sb, e))
-			largest_score = ent_score(sb, e);
+		if (largest_score < blame_entry_score(sb, e))
+			largest_score = blame_entry_score(sb, e);
 	}
 	max_orig_digits = decimal_width(longest_src_lines);
 	max_digits = decimal_width(longest_dst_lines);
@@ -2150,31 +560,12 @@ static void find_alignment(struct scoreboard *sb, int *option)
 		abbrev = auto_abbrev + 1;
 }
 
-/*
- * For debugging -- origin is refcounted, and this asserts that
- * we do not underflow.
- */
-static void sanity_check_refcnt(struct scoreboard *sb)
+static void sanity_check_on_fail(struct blame_scoreboard *sb, int baa)
 {
-	int baa = 0;
-	struct blame_entry *ent;
-
-	for (ent = sb->ent; ent; ent = ent->next) {
-		/* Nobody should have zero or negative refcnt */
-		if (ent->suspect->refcnt <= 0) {
-			fprintf(stderr, "%s in %s has negative refcnt %d\n",
-				ent->suspect->path,
-				oid_to_hex(&ent->suspect->commit->object.oid),
-				ent->suspect->refcnt);
-			baa = 1;
-		}
-	}
-	if (baa) {
-		int opt = 0160;
-		find_alignment(sb, &opt);
-		output(sb, opt);
-		die("Baa %d!", baa);
-	}
+	int opt = OUTPUT_SHOW_SCORE | OUTPUT_SHOW_NUMBER | OUTPUT_SHOW_NAME;
+	find_alignment(sb, &opt);
+	output(sb, opt);
+	die("Baa %d!", baa);
 }
 
 static unsigned parse_score(const char *arg)
@@ -2224,301 +615,6 @@ static int git_blame_config(const char *var, const char *value, void *cb)
 	return git_default_config(var, value, cb);
 }
 
-static void verify_working_tree_path(struct commit *work_tree, const char *path)
-{
-	struct commit_list *parents;
-	int pos;
-
-	for (parents = work_tree->parents; parents; parents = parents->next) {
-		const struct object_id *commit_oid = &parents->item->object.oid;
-		struct object_id blob_oid;
-		unsigned mode;
-
-		if (!get_tree_entry(commit_oid->hash, path, blob_oid.hash, &mode) &&
-		    sha1_object_info(blob_oid.hash, NULL) == OBJ_BLOB)
-			return;
-	}
-
-	pos = cache_name_pos(path, strlen(path));
-	if (pos >= 0)
-		; /* path is in the index */
-	else if (-1 - pos < active_nr &&
-		 !strcmp(active_cache[-1 - pos]->name, path))
-		; /* path is in the index, unmerged */
-	else
-		die("no such path '%s' in HEAD", path);
-}
-
-static struct commit_list **append_parent(struct commit_list **tail, const struct object_id *oid)
-{
-	struct commit *parent;
-
-	parent = lookup_commit_reference(oid);
-	if (!parent)
-		die("no such commit %s", oid_to_hex(oid));
-	return &commit_list_insert(parent, tail)->next;
-}
-
-static void append_merge_parents(struct commit_list **tail)
-{
-	int merge_head;
-	struct strbuf line = STRBUF_INIT;
-
-	merge_head = open(git_path_merge_head(), O_RDONLY);
-	if (merge_head < 0) {
-		if (errno == ENOENT)
-			return;
-		die("cannot open '%s' for reading", git_path_merge_head());
-	}
-
-	while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) {
-		struct object_id oid;
-		if (line.len < GIT_SHA1_HEXSZ || get_oid_hex(line.buf, &oid))
-			die("unknown line in '%s': %s", git_path_merge_head(), line.buf);
-		tail = append_parent(tail, &oid);
-	}
-	close(merge_head);
-	strbuf_release(&line);
-}
-
-/*
- * This isn't as simple as passing sb->buf and sb->len, because we
- * want to transfer ownership of the buffer to the commit (so we
- * must use detach).
- */
-static void set_commit_buffer_from_strbuf(struct commit *c, struct strbuf *sb)
-{
-	size_t len;
-	void *buf = strbuf_detach(sb, &len);
-	set_commit_buffer(c, buf, len);
-}
-
-/*
- * Prepare a dummy commit that represents the work tree (or staged) item.
- * Note that annotating work tree item never works in the reverse.
- */
-static struct commit *fake_working_tree_commit(struct diff_options *opt,
-					       const char *path,
-					       const char *contents_from)
-{
-	struct commit *commit;
-	struct origin *origin;
-	struct commit_list **parent_tail, *parent;
-	struct object_id head_oid;
-	struct strbuf buf = STRBUF_INIT;
-	const char *ident;
-	time_t now;
-	int size, len;
-	struct cache_entry *ce;
-	unsigned mode;
-	struct strbuf msg = STRBUF_INIT;
-
-	read_cache();
-	time(&now);
-	commit = alloc_commit_node();
-	commit->object.parsed = 1;
-	commit->date = now;
-	parent_tail = &commit->parents;
-
-	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_oid.hash, NULL))
-		die("no such ref: HEAD");
-
-	parent_tail = append_parent(parent_tail, &head_oid);
-	append_merge_parents(parent_tail);
-	verify_working_tree_path(commit, path);
-
-	origin = make_origin(commit, path);
-
-	ident = fmt_ident("Not Committed Yet", "not.committed.yet", NULL, 0);
-	strbuf_addstr(&msg, "tree 0000000000000000000000000000000000000000\n");
-	for (parent = commit->parents; parent; parent = parent->next)
-		strbuf_addf(&msg, "parent %s\n",
-			    oid_to_hex(&parent->item->object.oid));
-	strbuf_addf(&msg,
-		    "author %s\n"
-		    "committer %s\n\n"
-		    "Version of %s from %s\n",
-		    ident, ident, path,
-		    (!contents_from ? path :
-		     (!strcmp(contents_from, "-") ? "standard input" : contents_from)));
-	set_commit_buffer_from_strbuf(commit, &msg);
-
-	if (!contents_from || strcmp("-", contents_from)) {
-		struct stat st;
-		const char *read_from;
-		char *buf_ptr;
-		unsigned long buf_len;
-
-		if (contents_from) {
-			if (stat(contents_from, &st) < 0)
-				die_errno("Cannot stat '%s'", contents_from);
-			read_from = contents_from;
-		}
-		else {
-			if (lstat(path, &st) < 0)
-				die_errno("Cannot lstat '%s'", path);
-			read_from = path;
-		}
-		mode = canon_mode(st.st_mode);
-
-		switch (st.st_mode & S_IFMT) {
-		case S_IFREG:
-			if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV) &&
-			    textconv_object(read_from, mode, &null_oid, 0, &buf_ptr, &buf_len))
-				strbuf_attach(&buf, buf_ptr, buf_len, buf_len + 1);
-			else if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size)
-				die_errno("cannot open or read '%s'", read_from);
-			break;
-		case S_IFLNK:
-			if (strbuf_readlink(&buf, read_from, st.st_size) < 0)
-				die_errno("cannot readlink '%s'", read_from);
-			break;
-		default:
-			die("unsupported file type %s", read_from);
-		}
-	}
-	else {
-		/* Reading from stdin */
-		mode = 0;
-		if (strbuf_read(&buf, 0, 0) < 0)
-			die_errno("failed to read from stdin");
-	}
-	convert_to_git(path, buf.buf, buf.len, &buf, 0);
-	origin->file.ptr = buf.buf;
-	origin->file.size = buf.len;
-	pretend_sha1_file(buf.buf, buf.len, OBJ_BLOB, origin->blob_oid.hash);
-
-	/*
-	 * Read the current index, replace the path entry with
-	 * origin->blob_sha1 without mucking with its mode or type
-	 * bits; we are not going to write this index out -- we just
-	 * want to run "diff-index --cached".
-	 */
-	discard_cache();
-	read_cache();
-
-	len = strlen(path);
-	if (!mode) {
-		int pos = cache_name_pos(path, len);
-		if (0 <= pos)
-			mode = active_cache[pos]->ce_mode;
-		else
-			/* Let's not bother reading from HEAD tree */
-			mode = S_IFREG | 0644;
-	}
-	size = cache_entry_size(len);
-	ce = xcalloc(1, size);
-	oidcpy(&ce->oid, &origin->blob_oid);
-	memcpy(ce->name, path, len);
-	ce->ce_flags = create_ce_flags(0);
-	ce->ce_namelen = len;
-	ce->ce_mode = create_ce_mode(mode);
-	add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
-
-	cache_tree_invalidate_path(&the_index, path);
-
-	return commit;
-}
-
-static struct commit *find_single_final(struct rev_info *revs,
-					const char **name_p)
-{
-	int i;
-	struct commit *found = NULL;
-	const char *name = NULL;
-
-	for (i = 0; i < revs->pending.nr; i++) {
-		struct object *obj = revs->pending.objects[i].item;
-		if (obj->flags & UNINTERESTING)
-			continue;
-		obj = deref_tag(obj, NULL, 0);
-		if (obj->type != OBJ_COMMIT)
-			die("Non commit %s?", revs->pending.objects[i].name);
-		if (found)
-			die("More than one commit to dig from %s and %s?",
-			    revs->pending.objects[i].name, name);
-		found = (struct commit *)obj;
-		name = revs->pending.objects[i].name;
-	}
-	if (name_p)
-		*name_p = name;
-	return found;
-}
-
-static char *prepare_final(struct scoreboard *sb)
-{
-	const char *name;
-	sb->final = find_single_final(sb->revs, &name);
-	return xstrdup_or_null(name);
-}
-
-static const char *dwim_reverse_initial(struct scoreboard *sb)
-{
-	/*
-	 * DWIM "git blame --reverse ONE -- PATH" as
-	 * "git blame --reverse ONE..HEAD -- PATH" but only do so
-	 * when it makes sense.
-	 */
-	struct object *obj;
-	struct commit *head_commit;
-	struct object_id head_oid;
-
-	if (sb->revs->pending.nr != 1)
-		return NULL;
-
-	/* Is that sole rev a committish? */
-	obj = sb->revs->pending.objects[0].item;
-	obj = deref_tag(obj, NULL, 0);
-	if (obj->type != OBJ_COMMIT)
-		return NULL;
-
-	/* Do we have HEAD? */
-	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_oid.hash, NULL))
-		return NULL;
-	head_commit = lookup_commit_reference_gently(&head_oid, 1);
-	if (!head_commit)
-		return NULL;
-
-	/* Turn "ONE" into "ONE..HEAD" then */
-	obj->flags |= UNINTERESTING;
-	add_pending_object(sb->revs, &head_commit->object, "HEAD");
-
-	sb->final = (struct commit *)obj;
-	return sb->revs->pending.objects[0].name;
-}
-
-static char *prepare_initial(struct scoreboard *sb)
-{
-	int i;
-	const char *final_commit_name = NULL;
-	struct rev_info *revs = sb->revs;
-
-	/*
-	 * There must be one and only one negative commit, and it must be
-	 * the boundary.
-	 */
-	for (i = 0; i < revs->pending.nr; i++) {
-		struct object *obj = revs->pending.objects[i].item;
-		if (!(obj->flags & UNINTERESTING))
-			continue;
-		obj = deref_tag(obj, NULL, 0);
-		if (obj->type != OBJ_COMMIT)
-			die("Non commit %s?", revs->pending.objects[i].name);
-		if (sb->final)
-			die("More than one commit to dig up from, %s and %s?",
-			    revs->pending.objects[i].name,
-			    final_commit_name);
-		sb->final = (struct commit *) obj;
-		final_commit_name = revs->pending.objects[i].name;
-	}
-
-	if (!final_commit_name)
-		final_commit_name = dwim_reverse_initial(sb);
-	if (!final_commit_name)
-		die("No commit to dig up from?");
-	return xstrdup(final_commit_name);
-}
-
 static int blame_copy_callback(const struct option *option, const char *arg, int unset)
 {
 	int *opt = option->value;
@@ -2556,13 +652,11 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 {
 	struct rev_info revs;
 	const char *path;
-	struct scoreboard sb;
-	struct origin *o;
+	struct blame_scoreboard sb;
+	struct blame_origin *o;
 	struct blame_entry *ent = NULL;
 	long dashdash_pos, lno;
-	char *final_commit_name = NULL;
-	enum object_type type;
-	struct commit *final_commit = NULL;
+	struct progress_info pi = { NULL, 0 };
 
 	struct string_list range_list = STRING_LIST_INIT_NODUP;
 	int output_option = 0, opt = 0;
@@ -2712,11 +806,6 @@ parse_done:
 		opt |= (PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE |
 			PICKAXE_BLAME_COPY_HARDER);
 
-	if (!blame_move_score)
-		blame_move_score = BLAME_DEFAULT_MOVE_SCORE;
-	if (!blame_copy_score)
-		blame_copy_score = BLAME_DEFAULT_COPY_SCORE;
-
 	/*
 	 * We have collected options unknown to us in argv[1..unk]
 	 * which are to be passed to revision machinery if we are
@@ -2769,94 +858,13 @@ parse_done:
 
 	revs.disable_stdin = 1;
 	setup_revisions(argc, argv, &revs, NULL);
-	memset(&sb, 0, sizeof(sb));
 
+	init_scoreboard(&sb);
 	sb.revs = &revs;
-	if (!reverse) {
-		final_commit_name = prepare_final(&sb);
-		sb.commits.compare = compare_commits_by_commit_date;
-	}
-	else if (contents_from)
-		die(_("--contents and --reverse do not blend well."));
-	else {
-		final_commit_name = prepare_initial(&sb);
-		sb.commits.compare = compare_commits_by_reverse_commit_date;
-		if (revs.first_parent_only)
-			revs.children.name = NULL;
-	}
-
-	if (!sb.final) {
-		/*
-		 * "--not A B -- path" without anything positive;
-		 * do not default to HEAD, but use the working tree
-		 * or "--contents".
-		 */
-		setup_work_tree();
-		sb.final = fake_working_tree_commit(&sb.revs->diffopt,
-						    path, contents_from);
-		add_pending_object(&revs, &(sb.final->object), ":");
-	}
-	else if (contents_from)
-		die(_("cannot use --contents with final commit object name"));
-
-	if (reverse && revs.first_parent_only) {
-		final_commit = find_single_final(sb.revs, NULL);
-		if (!final_commit)
-			die(_("--reverse and --first-parent together require specified latest commit"));
-	}
-
-	/*
-	 * If we have bottom, this will mark the ancestors of the
-	 * bottom commits we would reach while traversing as
-	 * uninteresting.
-	 */
-	if (prepare_revision_walk(&revs))
-		die(_("revision walk setup failed"));
-
-	if (reverse && revs.first_parent_only) {
-		struct commit *c = final_commit;
-
-		sb.revs->children.name = "children";
-		while (c->parents &&
-		       oidcmp(&c->object.oid, &sb.final->object.oid)) {
-			struct commit_list *l = xcalloc(1, sizeof(*l));
-
-			l->item = c;
-			if (add_decoration(&sb.revs->children,
-					   &c->parents->item->object, l))
-				die("BUG: not unique item in first-parent chain");
-			c = c->parents->item;
-		}
-
-		if (oidcmp(&c->object.oid, &sb.final->object.oid))
-			die(_("--reverse --first-parent together require range along first-parent chain"));
-	}
-
-	if (is_null_oid(&sb.final->object.oid)) {
-		o = sb.final->util;
-		sb.final_buf = xmemdupz(o->file.ptr, o->file.size);
-		sb.final_buf_size = o->file.size;
-	}
-	else {
-		o = get_origin(&sb, sb.final, path);
-		if (fill_blob_sha1_and_mode(o))
-			die(_("no such path %s in %s"), path, final_commit_name);
-
-		if (DIFF_OPT_TST(&sb.revs->diffopt, ALLOW_TEXTCONV) &&
-		    textconv_object(path, o->mode, &o->blob_oid, 1, (char **) &sb.final_buf,
-				    &sb.final_buf_size))
-			;
-		else
-			sb.final_buf = read_sha1_file(o->blob_oid.hash, &type,
-						      &sb.final_buf_size);
-
-		if (!sb.final_buf)
-			die(_("cannot read blob %s for path %s"),
-			    oid_to_hex(&o->blob_oid),
-			    path);
-	}
-	num_read_blob++;
-	lno = prepare_lines(&sb);
+	sb.contents_from = contents_from;
+	sb.reverse = reverse;
+	setup_scoreboard(&sb, path, &o);
+	lno = sb.num_lines;
 
 	if (lno && !range_list.nr)
 		string_list_append(&range_list, "1");
@@ -2885,22 +893,13 @@ parse_done:
 
 	for (range_i = ranges.nr; range_i > 0; --range_i) {
 		const struct range *r = &ranges.ranges[range_i - 1];
-		long bottom = r->start;
-		long top = r->end;
-		struct blame_entry *next = ent;
-		ent = xcalloc(1, sizeof(*ent));
-		ent->lno = bottom;
-		ent->num_lines = top - bottom;
-		ent->suspect = o;
-		ent->s_lno = bottom;
-		ent->next = next;
-		origin_incref(o);
+		ent = blame_entry_prepend(ent, r->start, r->end, o);
 	}
 
 	o->suspects = ent;
 	prio_queue_put(&sb.commits, o->commit);
 
-	origin_decref(o);
+	blame_origin_decref(o);
 
 	range_set_release(&ranges);
 	string_list_clear(&range_list, 0);
@@ -2908,21 +907,38 @@ parse_done:
 	sb.ent = NULL;
 	sb.path = path;
 
+	if (blame_move_score)
+		sb.move_score = blame_move_score;
+	if (blame_copy_score)
+		sb.copy_score = blame_copy_score;
+
+	sb.debug = DEBUG;
+	sb.on_sanity_fail = &sanity_check_on_fail;
+
+	sb.show_root = show_root;
+	sb.xdl_opts = xdl_opts;
+	sb.no_whole_file_rename = no_whole_file_rename;
+
 	read_mailmap(&mailmap, NULL);
 
+	sb.found_guilty_entry = &found_guilty_entry;
+	sb.found_guilty_entry_data = &pi;
+	if (show_progress)
+		pi.progress = start_progress_delay(_("Blaming lines"),
+						   sb.num_lines, 50, 1);
+
 	assign_blame(&sb, opt);
 
+	stop_progress(&pi.progress);
+
 	if (!incremental)
 		setup_pager();
-
-	free(final_commit_name);
-
-	if (incremental)
+	else
 		return 0;
 
-	sb.ent = blame_sort(sb.ent, compare_blame_final);
+	blame_sort_final(&sb);
 
-	coalesce(&sb);
+	blame_coalesce(&sb);
 
 	if (!(output_option & OUTPUT_PORCELAIN))
 		find_alignment(&sb, &output_option);
@@ -2936,9 +952,9 @@ parse_done:
 	}
 
 	if (show_stats) {
-		printf("num read blob: %d\n", num_read_blob);
-		printf("num get patch: %d\n", num_get_patch);
-		printf("num commits: %d\n", num_commits);
+		printf("num read blob: %d\n", sb.num_read_blob);
+		printf("num get patch: %d\n", sb.num_get_patch);
+		printf("num commits: %d\n", sb.num_commits);
 	}
 	return 0;
 }
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 73c81f0cb1..4bffd7a2d8 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -5,6 +5,7 @@
  */
 #include "cache.h"
 #include "builtin.h"
+#include "diff.h"
 #include "parse-options.h"
 #include "userdiff.h"
 #include "streaming.h"
diff --git a/diff.c b/diff.c
index 48e5f9cb08..5275c4b780 100644
--- a/diff.c
+++ b/diff.c
@@ -5270,6 +5270,29 @@ size_t fill_textconv(struct userdiff_driver *driver,
 	return size;
 }
 
+int textconv_object(const char *path,
+		    unsigned mode,
+		    const struct object_id *oid,
+		    int oid_valid,
+		    char **buf,
+		    unsigned long *buf_size)
+{
+	struct diff_filespec *df;
+	struct userdiff_driver *textconv;
+
+	df = alloc_filespec(path);
+	fill_filespec(df, oid->hash, oid_valid, mode);
+	textconv = get_textconv(df);
+	if (!textconv) {
+		free_filespec(df);
+		return 0;
+	}
+
+	*buf_size = fill_textconv(textconv, df, buf);
+	free_filespec(df);
+	return 1;
+}
+
 void setup_diff_pager(struct diff_options *opt)
 {
 	/*
diff --git a/diff.h b/diff.h
index d75e6d15e2..67537f17ed 100644
--- a/diff.h
+++ b/diff.h
@@ -385,6 +385,13 @@ extern size_t fill_textconv(struct userdiff_driver *driver,
  */
 extern struct userdiff_driver *get_textconv(struct diff_filespec *one);
 
+/*
+ * Prepare diff_filespec and convert it using diff textconv API
+ * if the textconv driver exists.
+ * Return 1 if the conversion succeeds, 0 otherwise.
+ */
+extern int textconv_object(const char *path, unsigned mode, const struct object_id *oid, int oid_valid, char **buf, unsigned long *buf_size);
+
 extern int parse_rename_score(const char **cp_p);
 
 extern long parse_algorithm_value(const char *value);